[llvm] [NFC][AMDGPU] Use m_Intrinsic and m_AnyIntrinsic PatternMatch combinators across the backend (PR #194337)

[Matt Arsenault via llvm-commits]

================
@@ -359,28 +360,23 @@ bool isReallyAClobber(const Value *Ptr, MemoryDef *Def, AAResults *AA) {
   if (isa<FenceInst>(DefInst))
     return false;
 
-  if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(DefInst)) {
----------------
arsenm wrote:

Ditto 

https://github.com/llvm/llvm-project/pull/194337