[clang] [clang][test] Move offload tools tests to clang/test/OffloadTools (PR #198434)

[Alexey Bader via cfe-commits]

https://github.com/bader commented:

> The spirv-tools feature/substitution setup is carried over from Tooling's lit.local.cfg into a new lit.local.cfg in clang-linker-wrapper/, since the parent clang/test/lit.cfg.py does not set up that feature. The dead spirv-tools block is removed from Tooling/lit.local.cfg now that no tests there depend on it.

Why do OffloadTools tests depend on spirv-tools? I expect only SPIR-V backend tests need those.

https://github.com/llvm/llvm-project/pull/198434