Rollup merge of rust-lang#121513 - nshyrei:fix_tests_module, r=cuviper

Fix sgx unit test compilation

Fixes a compilation error:
```
error[E0583]: file not found for module `tests`
 --> library/std/src/sys/locks/rwlock/sgx.rs:2:1
  |
2 | mod tests;
  | ^^^^^^^^^^
  |
  = help: to create the module `tests`, create file "library/std/src/sys/locks/rwlock/sgx/tests.rs" or "library/std/src/sys/locks/rwlock/sgx/tests/mod.rs"
  = note: if there is a `mod tests` elsewhere in the crate already, import it with `use crate::...` instead

For more information about this error, try `rustc --explain E0583`.
error: could not compile `std` (lib test) due to 1 previous error`
```
When running command:
```
 `TF_BUILD=True RUST_TEST_THREADS=1 ./x.py test --stage 1 "library/std" tests/assembly tests/run-make --target=x86_64-fortanix-unknown-sgx --no-doc --exclude src/tools/linkchecker --exclude src/tools/rust-demangler --no-fail-fast 2>&1
```
The fix is done by moving a file to the location suggested by the compiler.

The issue was introduced by PR: rust-lang#121177