[llvm] [offload] Extend LIT infrastructure to allow using more tools (PR #124636)

[Shilei Tian via llvm-commits]

shiltian wrote:

Based on the description, I don't think this (aka. under offload subproject) is the right place for the test. You might want to test each component separately and as long as they all work as expected, the entire thing will simply work.

https://github.com/llvm/llvm-project/pull/124636