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

[Nick Sarnie via llvm-commits]

sarnex wrote:

The problem is getting `clang-linker-wrapper` to actually product full output when calling it directly is pretty difficult to do consistently in a test, and I need the full output because there's no other way to get the raw device code ELF which is what I want to test. It's dumped in `--save-temps` but I'd have to guess the file name which seems flaky.

For example, we need these args to `ld` to be correct to get full output in `clang-linker-wrapper`

```
"/lib64/ld-linux-x86-64.so.2"
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../lib64/Scrt1.o" 
"/usr/lib/gcc/x86_64-redhat-linux/11/../../../../lib64/crti.o" 
etc
```

Even if I ship some object file or something to simplify the part before `clang-linker-wrapper`, we still have the above problem.

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