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

[Vikram Hegde via cfe-commits]

vikramRH wrote:

> @jayfoad's testcase fails and the same test should be repeated for all 3 intrinsics

added MIR tests for 3 intrinsics. The issue is that Im not able to attach the glue nodes to newly created laneop pieces since they fail at selection. https://github.com/llvm/llvm-project/pull/87509 should enable this,

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