Shorten span of panic failures in const context

Previously, we included a redundant prefix on the panic message and a postfix of the location of the panic. The prefix didn't carry any additional information beyond "something failed", and the location of the panic is redundant with the diagnostic's span, which gets printed out even if its code is not shown.

```
error[E0080]: evaluation of constant value failed
  --> $DIR/assert-type-intrinsics.rs:11:9
   |
LL |         MaybeUninit::<!>::uninit().assume_init();
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation panicked: aborted execution: attempted to instantiate uninhabited type `!`
```

```
error[E0080]: evaluation of `Fail::<i32>::C` failed
  --> $DIR/collect-in-dead-closure.rs:9:19
   |
LL |     const C: () = panic!();
   |                   ^^^^^^^^ evaluation panicked: explicit panic
   |
   = note: this error originates in the macro
`$crate::panic::panic_2015` which comes from the expansion of the macro
`panic` (in Nightly builds, run with -Z macro-backtrace for more info)
```

```
error[E0080]: evaluation of constant value failed
  --> $DIR/uninhabited.rs:41:9
   |
LL |         assert!(false);
   |         ^^^^^^^^^^^^^^ evaluation panicked: assertion failed: false
   |
   = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
```

---

When the primary span for a const error is the same as the first frame in the const error report, skip it.

```
error[E0080]: evaluation of constant value failed
  --> $DIR/issue-88434-removal-index-should-be-less.rs:3:24
   |
LL | const _CONST: &[u8] = &f(&[], |_| {});
   |                        ^^^^^^^^^^^^^^ evaluation panicked: explicit panic
   |
note: inside `f::<{closure@$DIR/issue-88434-removal-index-should-be-less.rs:3:31: 3:34}>`
  --> $DIR/issue-88434-removal-index-should-be-less.rs:10:5
   |
LL |     panic!()
   |     ^^^^^^^^ the failure occurred here
   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
```
instead of
```
error[E0080]: evaluation of constant value failed
  --> $DIR/issue-88434-removal-index-should-be-less.rs:10:5
   |
LL |     panic!()
   |     ^^^^^^^^ explicit panic
   |
note: inside `f::<{closure@$DIR/issue-88434-removal-index-should-be-less.rs:3:31: 3:34}>`
  --> $DIR/issue-88434-removal-index-should-be-less.rs:10:5
   |
LL |     panic!()
   |     ^^^^^^^^
note: inside `_CONST`
  --> $DIR/issue-88434-removal-index-should-be-less.rs:3:24
   |
LL | const _CONST: &[u8] = &f(&[], |_| {});
   |                        ^^^^^^^^^^^^^^
   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
```

---

Revert order of constant evaluation errors

Point at the code the user wrote first and std functions last.

```
error[E0080]: evaluation of constant value failed
  --> $DIR/const-errs-dont-conflict-103369.rs:5:25
   |
LL | impl ConstGenericTrait<{my_fn(1)}> for () {}
   |                         ^^^^^^^^ evaluation panicked: Some error occurred
   |
note: called from `my_fn`
  --> $DIR/const-errs-dont-conflict-103369.rs:10:5
   |
LL |     panic!("Some error occurred");
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
```
instead of
```
error[E0080]: evaluation of constant value failed
  --> $DIR/const-errs-dont-conflict-103369.rs:10:5
   |
LL |     panic!("Some error occurred");
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Some error occurred
   |
note: called from `<() as ConstGenericTrait<{my_fn(1)}>>::{constant#0}`
  --> $DIR/const-errs-dont-conflict-103369.rs:5:25
   |
LL | impl ConstGenericTrait<{my_fn(1)}> for () {}
   |                         ^^^^^^^^
   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
```

5 files changed, 19 insertions, 33 deletions

diff --git a/tests/ui/consts/miri_unleashed/abi-mismatch.rs b/tests/ui/consts/miri_unleashed/abi-mismatch.rs
index da5b1dd5802..ea640ae78d5 100644
--- a/tests/ui/consts/miri_unleashed/abi-mismatch.rs
+++ b/tests/ui/consts/miri_unleashed/abi-mismatch.rs
@@ -4,13 +4,12 @@
 const extern "C" fn c_fn() {}
 
 const fn call_rust_fn(my_fn: extern "Rust" fn()) {
-    my_fn();
-    //~^ ERROR could not evaluate static initializer
-    //~| NOTE calling a function with calling convention C using calling convention Rust
-    //~| NOTE inside `call_rust_fn`
+    my_fn(); //~ NOTE inside `call_rust_fn`
+    //~^ NOTE the failure occurred here
 }
 
 static VAL: () = call_rust_fn(unsafe { std::mem::transmute(c_fn as extern "C" fn()) });
-//~^ NOTE inside `VAL`
+//~^ ERROR could not evaluate static initializer
+//~| NOTE calling a function with calling convention C using calling convention Rust
 
 fn main() {}
diff --git a/tests/ui/consts/miri_unleashed/abi-mismatch.stderr b/tests/ui/consts/miri_unleashed/abi-mismatch.stderr
index 639795efae7..88623b134b0 100644
--- a/tests/ui/consts/miri_unleashed/abi-mismatch.stderr
+++ b/tests/ui/consts/miri_unleashed/abi-mismatch.stderr
@@ -1,19 +1,14 @@
 error[E0080]: could not evaluate static initializer
-  --> $DIR/abi-mismatch.rs:7:5
+  --> $DIR/abi-mismatch.rs:11:18
    |
-LL |     my_fn();
-   |     ^^^^^^^ calling a function with calling convention C using calling convention Rust
+LL | static VAL: () = call_rust_fn(unsafe { std::mem::transmute(c_fn as extern "C" fn()) });
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ calling a function with calling convention C using calling convention Rust
    |
 note: inside `call_rust_fn`
   --> $DIR/abi-mismatch.rs:7:5
    |
 LL |     my_fn();
-   |     ^^^^^^^
-note: inside `VAL`
-  --> $DIR/abi-mismatch.rs:13:18
-   |
-LL | static VAL: () = call_rust_fn(unsafe { std::mem::transmute(c_fn as extern "C" fn()) });
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^ the failure occurred here
 
 warning: skipping const checks
    |
diff --git a/tests/ui/consts/miri_unleashed/assoc_const.rs b/tests/ui/consts/miri_unleashed/assoc_const.rs
index db37197f190..96b47ff4e5e 100644
--- a/tests/ui/consts/miri_unleashed/assoc_const.rs
+++ b/tests/ui/consts/miri_unleashed/assoc_const.rs
@@ -9,7 +9,7 @@ trait Foo<T> {
 }
 
 trait Bar<T, U: Foo<T>> {
-    const F: u32 = (U::X, 42).1;
+    const F: u32 = (U::X, 42).1; //~ ERROR
 }
 
 impl Foo<u32> for () {
@@ -26,5 +26,5 @@ fn main() {
     // this is fine, but would have been forbidden by the static checks on `F`
     let x = <() as Bar<u32, ()>>::F;
     // this test only causes errors due to the line below, so post-monomorphization
-    let y = <String as Bar<Vec<u32>, String>>::F; //~ constant
+    let y = <String as Bar<Vec<u32>, String>>::F;
 }
diff --git a/tests/ui/consts/miri_unleashed/assoc_const.stderr b/tests/ui/consts/miri_unleashed/assoc_const.stderr
index 3303a784265..f259765f6e5 100644
--- a/tests/ui/consts/miri_unleashed/assoc_const.stderr
+++ b/tests/ui/consts/miri_unleashed/assoc_const.stderr
@@ -1,17 +1,13 @@
-error[E0080]: evaluation of `<String as Bar<Vec<u32>, String>>::F` failed
-  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+error[E0080]: evaluation of `std::ptr::drop_in_place::<Vec<u32>> - shim(Some(Vec<u32>))` failed
+  --> $DIR/assoc_const.rs:12:31
    |
-   = note: calling non-const function `<Vec<u32> as Drop>::drop`
+LL |     const F: u32 = (U::X, 42).1;
+   |                               ^ calling non-const function `<Vec<u32> as Drop>::drop`
    |
-note: inside `std::ptr::drop_in_place::<Vec<u32>> - shim(Some(Vec<u32>))`
-  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
 note: inside `std::ptr::drop_in_place::<(Vec<u32>, u32)> - shim(Some((Vec<u32>, u32)))`
   --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-note: inside `<String as Bar<Vec<u32>, String>>::F`
-  --> $DIR/assoc_const.rs:12:31
-   |
-LL |     const F: u32 = (U::X, 42).1;
-   |                               ^
+note: inside `std::ptr::drop_in_place::<Vec<u32>> - shim(Some(Vec<u32>))`
+  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
 
 note: erroneous constant encountered
   --> $DIR/assoc_const.rs:29:13
diff --git a/tests/ui/consts/miri_unleashed/drop.stderr b/tests/ui/consts/miri_unleashed/drop.stderr
index 5c415b5bac1..40a29d5a819 100644
--- a/tests/ui/consts/miri_unleashed/drop.stderr
+++ b/tests/ui/consts/miri_unleashed/drop.stderr
@@ -1,15 +1,11 @@
 error[E0080]: could not evaluate static initializer
-  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+  --> $DIR/drop.rs:17:1
    |
-   = note: calling non-const function `<Vec<i32> as Drop>::drop`
+LL | };
+   | ^ calling non-const function `<Vec<i32> as Drop>::drop`
    |
 note: inside `std::ptr::drop_in_place::<Vec<i32>> - shim(Some(Vec<i32>))`
   --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-note: inside `TEST_BAD`
-  --> $DIR/drop.rs:17:1
-   |
-LL | };
-   | ^
 
 warning: skipping const checks
    |