Rollup of 5 pull requests

Successful merges:

 - rust-lang#134799 (nits: Cleanups in `librustdoc::clean`)
 - rust-lang#134851 (docs: inline `alloc::ffi::c_str` types to `alloc::ffi`)
 - rust-lang#134869 (Bump compiler cc)
 - rust-lang#134876 (bootstrap: Consolidate the macros for declaring compiletest test suites)
 - rust-lang#134883 (bootstrap: Fix `./x check bootstrap` by moving `shared_helpers::tests`)

r? `@ghost`
`@rustbot` modify labels: rollup

Rollup merge of rust-lang#134883 - Zalathar:shared-helpers, r=clubby789

bootstrap: Fix `./x check bootstrap` by moving `shared_helpers::tests`

Running `./x check bootstrap` currently doesn't work, because it builds the bootstrap shim binaries with `cfg(test)`, and those binaries can't find a `tests` submodule when they include `shared_helpers.rs` via `#[path]`.

This PR fixes that by taking the tests module and moving it to `super::tests::shared_helpers_tests` instead.

(The extra `tests` submodule prevents tidy from complaining about unit tests that aren't in a dedicated tests module.)

---

It would be nice to also run `./x check bootstrap compiletest` in CI, so that this and rust-lang#134848 don't regress, but I didn't want to bundle that change with this fix.

…ts, r=Kobzol

Fix `./x check bootstrap` (again)

Redoes rust-lang#134883 and reverts 40c2ca9 from rust-lang#142416. Unfortunately I missed this during review.

- Commit 1: Reverts 40c2ca9 and re-applies rust-lang#134883.
- Commit 2: Check `./x check bootstrap` in `pr-check-1` to catch "obvious" problems like this.

r? Kobzol

…ts, r=Kobzol

Fix `./x check bootstrap` (again)

Redoes rust-lang#134883 and reverts 40c2ca9 from rust-lang#142416. Unfortunately I missed this during review.

- Commit 1: Reverts 40c2ca9 and re-applies rust-lang#134883.
- Commit 2: Check `./x check bootstrap` in `pr-check-1` to catch "obvious" problems like this.

r? Kobzol

…ts, r=Kobzol

Fix `./x check bootstrap` (again)

Redoes rust-lang#134883 and reverts 40c2ca9 from rust-lang#142416. Unfortunately I missed this during review.

- Commit 1: Reverts 40c2ca9 and re-applies rust-lang#134883.
- Commit 2: Check `./x check bootstrap` in `pr-check-1` to catch "obvious" problems like this.

r? Kobzol

…ts, r=Kobzol

Fix `./x check bootstrap` (again)

Redoes rust-lang#134883 and reverts 40c2ca9 from rust-lang#142416. Unfortunately I missed this during review.

- Commit 1: Reverts 40c2ca9 and re-applies rust-lang#134883.
- Commit 2: Check `./x check bootstrap` in `pr-check-1` to catch "obvious" problems like this.

r? Kobzol

…ts, r=Kobzol

Fix `./x check bootstrap` (again)

Redoes rust-lang#134883 and reverts 40c2ca9 from rust-lang#142416. Unfortunately I missed this during review.

- Commit 1: Reverts 40c2ca9 and re-applies rust-lang#134883.
- Commit 2: Check `./x check bootstrap` in `pr-check-1` to catch "obvious" problems like this.

r? Kobzol

…ts, r=Kobzol

Fix `./x check bootstrap` (again)

Redoes rust-lang#134883 and reverts 40c2ca9 from rust-lang#142416. Unfortunately I missed this during review.

- Commit 1: Reverts 40c2ca9 and re-applies rust-lang#134883.
- Commit 2: Check `./x check bootstrap` in `pr-check-1` to catch "obvious" problems like this.

r? Kobzol

Rollup merge of #144445 - jieyouxu:revert-shared_helpers_tests, r=Kobzol

Fix `./x check bootstrap` (again)

Redoes #134883 and reverts 40c2ca9 from #142416. Unfortunately I missed this during review.

- Commit 1: Reverts 40c2ca9 and re-applies #134883.
- Commit 2: Check `./x check bootstrap` in `pr-check-1` to catch "obvious" problems like this.

r? Kobzol