[llvm] [SPIR-V] Support extension toggling and enabling all (PR #85503)

[Arvind Sudarsanam via llvm-commits]

https://github.com/asudarsa commented:

Looks good overall. Minor suggestions from the perspective of keeping this in sync with the translator. please feel free to address as convenient.

Thanks

https://github.com/llvm/llvm-project/pull/85503