Auto merge of #106458 - albertlarsan68:move-tests, r=jyn514

Move src/test to the root

See MCP at rust-lang/compiler-team#573

There may be more changes needed.

The first commit is just the move of the files:
You can check that the first commit did not do anything else than renames by running
```
git diff --diff-filter=r -M100% <rust-lang remote>/master <first commit hash>
```
The output should be empty, because the filter excludes renames, and the match threshold for qualifying a rename is 100%.

The second one is mostly a "find and replace" of `src/test` to `tests` and whatever is needed to make CI pass.

What is left to do:
---

- [x] Move directory
- [ ] Change references to `src/test`
    - [x] Change references in-tree
    - [ ] Change references in submodules / out-of-tree docs
- [x] Make CI pass:
    - [x] Fix tidy
    - [x] Fix tests
    - [x] Bless tests if needed (shouldn't normally)
- [ ] Merge it !

1 files changed, 23 insertions, 0 deletions

diff --git a/tests/codegen/slice_as_from_ptr_range.rs b/tests/codegen/slice_as_from_ptr_range.rs
new file mode 100644
index 00000000000..0e3fefd9728
--- /dev/null
+++ b/tests/codegen/slice_as_from_ptr_range.rs
@@ -0,0 +1,23 @@
+// compile-flags: -O
+// only-64bit (because we're using [ui]size)
+// ignore-debug (because the assertions get in the way)
+// min-llvm-version: 15.0 (because this is a relatively new instcombine)
+
+#![crate_type = "lib"]
+#![feature(slice_from_ptr_range)]
+
+// This is intentionally using a non-power-of-two array length,
+// as that's where the optimization differences show up
+
+// CHECK-LABEL: @flatten_via_ptr_range
+#[no_mangle]
+pub fn flatten_via_ptr_range(slice_of_arrays: &[[i32; 13]]) -> &[i32] {
+    // CHECK-NOT: lshr
+    // CHECK-NOT: udiv
+    // CHECK: mul nuw nsw i64 %{{.+}}, 13
+    // CHECK-NOT: lshr
+    // CHECK-NOT: udiv
+    let r = slice_of_arrays.as_ptr_range();
+    let r = r.start.cast()..r.end.cast();
+    unsafe { core::slice::from_ptr_range(r) }
+}