[clang] [llvm] [AMDGPU] Extend readlane, writelane and readfirstlane intrinsic lowering for generic types (PR #89217)

[Vikram Hegde via cfe-commits]

vikramRH wrote:

> You should add the mentioned convergence-tokens.ll test function

Added the test in a separate test file

https://github.com/llvm/llvm-project/pull/89217