[llvm] [AMDGPU] Add another SIFoldOperands instance after shrink (PR #67878)

[Stanislav Mekhanoshin via llvm-commits]

rampitec wrote:

> If this goes in, as a follow up, could try removing `SIShrinkInstructions::foldImmediates`? It ought to be redundant.

Sure, I will see if it can be removed now.

https://github.com/llvm/llvm-project/pull/67878