[llvm] [offload] Fix finding amdgpu/nvptx-arch to generate tests (PR #135072)

[Joel E. Denny via llvm-commits]

jdenny-ornl wrote:

Thanks for the quick reviews.

Not sure what you mean by "works".  For me, the offload tests just weren't generated, so everything quietly succeeded.

https://github.com/llvm/llvm-project/pull/135072