[x86] add more tests for LowerToHorizontalOp(); NFC

These tests show missed optimizations and a miscompile
similar to PR40243 - https://bugs.llvm.org/show_bug.cgi?id=40243


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@350533 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed