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, 22 insertions, 0 deletions

diff --git a/tests/ui/stdlib-unit-tests/not-sync.rs b/tests/ui/stdlib-unit-tests/not-sync.rs
new file mode 100644
index 00000000000..f4648994fa9
--- /dev/null
+++ b/tests/ui/stdlib-unit-tests/not-sync.rs
@@ -0,0 +1,22 @@
+use std::cell::{Cell, RefCell};
+use std::rc::{Rc, Weak};
+use std::sync::mpsc::{Receiver, Sender};
+
+fn test<T: Sync>() {}
+
+fn main() {
+    test::<Cell<i32>>();
+    //~^ ERROR `Cell<i32>` cannot be shared between threads safely [E0277]
+    test::<RefCell<i32>>();
+    //~^ ERROR `RefCell<i32>` cannot be shared between threads safely [E0277]
+
+    test::<Rc<i32>>();
+    //~^ ERROR `Rc<i32>` cannot be shared between threads safely [E0277]
+    test::<Weak<i32>>();
+    //~^ ERROR `std::rc::Weak<i32>` cannot be shared between threads safely [E0277]
+
+    test::<Receiver<i32>>();
+    //~^ ERROR `std::sync::mpsc::Receiver<i32>` cannot be shared between threads safely [E0277]
+    test::<Sender<i32>>();
+    //~^ ERROR `Sender<i32>` cannot be shared between threads safely [E0277]
+}