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, 12 insertions, 0 deletions

diff --git a/tests/ui/impl-trait/issues/issue-83929-impl-trait-in-generic-default.rs b/tests/ui/impl-trait/issues/issue-83929-impl-trait-in-generic-default.rs
new file mode 100644
index 00000000000..344f359529b
--- /dev/null
+++ b/tests/ui/impl-trait/issues/issue-83929-impl-trait-in-generic-default.rs
@@ -0,0 +1,12 @@
+struct Foo<T = impl Copy>(T);
+//~^ ERROR `impl Trait` only allowed in function and inherent method return types
+
+type Result<T, E = impl std::error::Error> = std::result::Result<T, E>;
+//~^ ERROR `impl Trait` only allowed in function and inherent method return types
+
+// should not cause ICE
+fn x() -> Foo {
+    Foo(0)
+}
+
+fn main() -> Result<()> {}