[SLPVectorizer][X86] Tests to show missed buildvector sitofp/fptosi vectorizations

e.g.
buildvector(sitofp(i32), sitofp(i32), sitofp(i32), sitofp(i32)) --> sitofp(buildvector(i32, i32, i32, i32))

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288807 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed