[llvm] [SPIRV] Addition of extension SPV_KHR_non_semantic_info (PR #165302)

[Nathan Gauër via llvm-commits]

Keenuts wrote:

You might want to take a look at:
https://github.khronos.org/SPIRV-Registry/extensions/KHR/SPV_KHR_relaxed_extended_instruction.html

and

https://github.com/KhronosGroup/SPIRV-Tools/pull/5698/files

When declaring a class with methods, you can end-up with forward references in non-semantic info. In such case, you need to generate OpExtInstWithForwardRef instruction instead, and user this extension.

https://github.com/llvm/llvm-project/pull/165302