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, 54 insertions, 0 deletions

diff --git a/tests/ui/structs-enums/align-enum.rs b/tests/ui/structs-enums/align-enum.rs
new file mode 100644
index 00000000000..fa872caa3b4
--- /dev/null
+++ b/tests/ui/structs-enums/align-enum.rs
@@ -0,0 +1,54 @@
+// run-pass
+#![allow(dead_code)]
+
+use std::mem;
+
+// Raising alignment
+#[repr(align(16))]
+enum Align16 {
+    Foo { foo: u32 },
+    Bar { bar: u32 },
+}
+
+// Raise alignment by maximum
+#[repr(align(1), align(16))]
+#[repr(align(32))]
+#[repr(align(4))]
+enum Align32 {
+    Foo,
+    Bar,
+}
+
+// Not reducing alignment
+#[repr(align(4))]
+enum AlsoAlign16 {
+    Foo { limb_with_align16: Align16 },
+    Bar,
+}
+
+// No niche for discriminant when used as limb
+#[repr(align(16))]
+struct NoNiche16(u64, u64);
+
+// Discriminant will require extra space, but enum needs to stay compatible
+// with alignment 16
+#[repr(align(1))]
+enum AnotherAlign16 {
+    Foo { limb_with_noniche16: NoNiche16 },
+    Bar,
+    Baz,
+}
+
+fn main() {
+    assert_eq!(mem::align_of::<Align16>(), 16);
+    assert_eq!(mem::size_of::<Align16>(), 16);
+
+    assert_eq!(mem::align_of::<Align32>(), 32);
+    assert_eq!(mem::size_of::<Align32>(), 32);
+
+    assert_eq!(mem::align_of::<AlsoAlign16>(), 16);
+    assert_eq!(mem::size_of::<AlsoAlign16>(), 16);
+
+    assert_eq!(mem::align_of::<AnotherAlign16>(), 16);
+    assert_eq!(mem::size_of::<AnotherAlign16>(), 32);
+}