compiletest: aggressive_rm_rf might not be aggressive enough on non-Windows platforms

[jieyouxu]

rust/src/tools/compiletest/src/runtest.rs

Lines 3420 to 3441 in bbe9a9c

	fn aggressive_rm_rf(&self, path: &Path) -> io::Result<()> {
	for e in path.read_dir()? {
	let entry = e?;
	let path = entry.path();
	if entry.file_type()?.is_dir() {
	self.aggressive_rm_rf(&path)?;
	} else {
	// Remove readonly files as well on windows (by default we can't)
	fs::remove_file(&path).or_else(|e| {
	if cfg!(windows) && e.kind() == io::ErrorKind::PermissionDenied {
	let mut meta = entry.metadata()?.permissions();
	meta.set_readonly(false);
	fs::set_permissions(&path, meta)?;
	fs::remove_file(&path)
	} else {
	Err(e)
	}
	})?;
	}
	}
	fs::remove_dir(path)
	}

aggressive_rm_rf seems to only account for read-only files in Windows (and tries really hard to rm -rf), but does not try as hard on Linux or macOS or other non-Windows platforms. This can pose issues to tests that modifies file or folder permissions in one way or another that could cause fs::remove_file to fail, which can lead to artifacts lingering around and cause tests results to not be reproducible.

[jieyouxu]

Re-opening due to revert #129413.