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, 25 insertions, 0 deletions

diff --git a/tests/ui/consts/const-int-arithmetic-overflow.rs b/tests/ui/consts/const-int-arithmetic-overflow.rs
new file mode 100644
index 00000000000..6446e94513c
--- /dev/null
+++ b/tests/ui/consts/const-int-arithmetic-overflow.rs
@@ -0,0 +1,25 @@
+// run-pass
+// compile-flags: -O
+
+// Make sure arithmetic unary/binary ops actually return the right result, even when overflowing.
+// We have to put them in `const fn` and turn on optimizations to avoid overflow checks.
+
+const fn add(x: i8, y: i8) -> i8 { x+y }
+const fn sub(x: i8, y: i8) -> i8 { x-y }
+const fn mul(x: i8, y: i8) -> i8 { x*y }
+// div and rem are always checked, so we cannot test their result in case of overflow.
+const fn neg(x: i8) -> i8 { -x }
+
+fn main() {
+    const ADD_OFLOW: i8 = add(100, 100);
+    assert_eq!(ADD_OFLOW, -56);
+
+    const SUB_OFLOW: i8 = sub(100, -100);
+    assert_eq!(SUB_OFLOW, -56);
+
+    const MUL_OFLOW: i8 = mul(-100, -2);
+    assert_eq!(MUL_OFLOW, -56);
+
+    const NEG_OFLOW: i8 = neg(-128);
+    assert_eq!(NEG_OFLOW, -128);
+}