lit doesn't delete `%t` directories

[llvmbot]

Bugzilla Link	9904
Version	trunk
OS	Linux
Reporter	LLVM Bugzilla Contributor
CC	@jryans,@mattmccutchen-cci,@modocache

Extended Description

There's a bunch of tests now that use rm -rf %t to clear out directories they create in between runs. This is something that lit should do, it should clear out files or directories named %t*.

[mattmccutchen-cci]

We (https://github.com/correctcomputation/checkedc-clang/tree/main/clang/test/3C) are affected by this too, and I researched the current status a bit. It looks like someone tried to add the feature to lit back in 2017 (https://reviews.llvm.org/D34732), but the change was immediately reverted because it broke something (https://reviews.llvm.org/rGe9db96e6d9eb2fd03d35d884e53998861b80a178). I wasn't able to find any more details about what broke or any other discussion about the potential feature on the web. Is any more information available that I missed?