[clang] [llvm] [Clang] Add env var for nvptx-arch/amdgpu-arch timeout (PR #102521)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 commented:

Maybe we should bump the default time up? I don't know what's reasonable in this area, but the GPU drivers have a bad habit of timing out. I think you could document the env var in the error message itself, and `-1` should mean effectively infinite.

https://github.com/llvm/llvm-project/pull/102521