[llvm] [AMDGPU] Lower `llvm.amdgcn.queue.ptr` instrinsic to using implicit kernel argument if feasible (PR #103490)

[Shilei Tian via llvm-commits]

shiltian wrote:

> But you still can use the queue pointer, it's not gone. The logic should be able to differentiate should not use queue pointer and queue pointer does not exist

But the thing is, the queue pointer (the two SGPRs) are never set in COV5. If you still want to use them, you basically have to revert many patches that @changpeng has done.

https://github.com/llvm/llvm-project/pull/103490