[llvm] [SPIRV] Add radians intrinsic (PR #110800)

[Farzon Lotfi via llvm-commits]

https://github.com/farzonl requested changes to this pull request.

You need to rebase, you shouldn't need a custom select for radians because it's spec'd out in GLSL extensions: https://registry.khronos.org/SPIR-V/specs/1.0/GLSL.std.450.html 

https://github.com/llvm/llvm-project/pull/110800