[llvm] [VPlan] Only store RecurKind + FastMathFlags in VPReductionRecipe. NFCI (PR #131300)

[Florian Hahn via llvm-commits]

fhahn wrote:

I think 

> > LGTM, as long as it doesn't complicate #113903
> 
> I'm not in a rush so I can wait until #113903 lands first, and then I can rebase this on top of it @ElvisWang123

Just looked and if that type is the only thing that needs storing in #113903 I think it should be fine to merge this one now

https://github.com/llvm/llvm-project/pull/131300