[clang] [Clang][OpenCL][AMDGPU] OpenCL Kernel stubs should be assigned alwaysinline attribute (PR #137769)

[Christudasan Devadasan via cfe-commits]

cdevadas wrote:

> Apparently the inliner has an arbitrary size threshold even for single uses. I don't see the point of that, we should probably remove that

I had a similar concern. For a single use and in this case especially when the call `Inst` is the only instruction in the Caller, it should have been allowed to inline.

https://github.com/llvm/llvm-project/pull/137769