[X86] Remove -costmodel-reduxcost=true from the experimental vector reduction intrinsic tests as it appears to be unnecessary. NFC

I think this has something to do with matching reductions from extractelement, binops, and shuffles. But we're not matching here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348340 91177308-0d34-0410-b5e6-96231b3b80d8
18 files changed