FindCUDA error handling (#44236)
Summary:
Check return code of `nvcc --version` and if it's not zero, print warning and mark CUDA as not found.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44236
Test Plan: Run `CUDA_NVCC_EXECUTABLE=/foo/bar cmake ../`
Reviewed By: ezyang
Differential Revision: D23552336
Pulled By: malfet
fbshipit-source-id: cf9387140a8cdbc8dab12fcc4bfaf55ae8e6a502
