[llvm] [NVPTX] Add ptxas verification and kernel test to sm-version test (PR #139543)

[Puja Saha via llvm-commits]

puja2196 wrote:

I've addressed the review feedback:
1. Removed the unnecessary comment about ptxas availability
2. Removed the test kernel functions as they're not needed with ptxas verification

The ptxas verification tests remain in place as they're the core purpose of this PR.

https://github.com/llvm/llvm-project/pull/139543