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, 0 insertions, 14 deletions

diff --git a/src/test/ui/self/string-self-append.rs b/src/test/ui/self/string-self-append.rs
deleted file mode 100644
index e63dc0090cb..00000000000
--- a/src/test/ui/self/string-self-append.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-// run-pass
-pub fn main() {
-    // Make sure we properly handle repeated self-appends.
-    let mut a: String = "A".to_string();
-    let mut i = 20;
-    let mut expected_len = 1;
-    while i > 0 {
-        println!("{}", a.len());
-        assert_eq!(a.len(), expected_len);
-        a = format!("{}{}", a, a);
-        i -= 1;
-        expected_len *= 2;
-    }
-}