Auto merge of #125827 - jieyouxu:rmake-separate-tmp-dir, r=onur-ozkan

compiletest: split rmake.rs executable from scratch directory

When implementing support for rmake.rs, I copied over the `$TMPDIR` directory logic from the legacy Makefile setup. In doing so, I also compiled recipe `rmake.rs` into executables which unfortunately are placed into `$TMPDIR` as well.

This causes a problem on Windows (as observed in PRs like https://github.com/rust-lang/rust/pull/125752#issuecomment-2142577084) where:

- The `rmake.exe` executable is placed in `$TMPDIR`.
- We run the `rmake.exe` as a process.
- The process uses `rmake.exe` inside `$TMPDIR`.
- Windows prevents the .exe file from being deleted when the process is still alive.
- The recipe test code tries to `remove_dir_all($TMPDIR)`, which fails with access denied because `rmake.exe` is still being used.

We fix this by separating the recipe executable and the output artifacts directory:

```
base_dir/
    rmake.exe
    rmake_out/
```

We construct a base directory, unique to each run-make test, under which we place rmake.exe alongside a `rmake_out/` directory. This `rmake_out/` directory is what is passed to rmake.rs tests as `$TMPDIR`, so now `remove_dir_all($TMPDIR)` has a chance to succeed because it no longer contains `rmake.exe`.

This wasn't a problem for Makefile tests because there's no exe file under `$TMPDIR` whose process is still running when `rm -rf $TMPDIR` is called.

try-job: x86_64-msvc

0 files changed, 0 insertions, 0 deletions