[llvm] [VPlan] Change parent of VPReductionRecipe to VPRecipeWithIRFlags. NFC (PR #130881)

[Luke Lau via llvm-commits]

================
@@ -2369,8 +2372,7 @@ void VPReductionEVLRecipe::print(raw_ostream &O, const Twine &Indent,
   O << " = ";
   getChainOp()->printAsOperand(O, SlotTracker);
   O << " +";
-  if (isa<FPMathOperator>(getUnderlyingInstr()))
----------------
lukel97 wrote:

>From what I understand an integer RecurrenceDescriptor has all fast math flags set:

https://github.com/llvm/llvm-project/blob/6eb32a2fa0d16bea03f22dd2078f53da6d9352cd/llvm/lib/Analysis/IVDescriptors.cpp#L286-L288

So currently today an integer VPReductionRecipe will use a builder with all fast math flags set:

```c++
  IRBuilderBase::FastMathFlagGuard FMFGuard(State.Builder);
  State.Builder.setFastMathFlags(RdxDesc.getFastMathFlags());
```


https://github.com/llvm/llvm-project/pull/130881