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

[Nick Sarnie via llvm-commits]

sarnex wrote:

Do you have a suggested location? The change will be inside `clang-linker-wrapper` (well code directly called by it), and I want to do a full OpenMP compile on source code which will include the `clang-linker-wrapper` call internally. I didn't think I could assume OpenMP was available inside `clang`, and I didn't see any places where we actually tested `clang-linker-wrapper` directly, only tool checks in the driver.

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