[X86] Add tests showing inability of vector non-temporal load/store intrinsic to force pointer alignment (PR33830)

Clang specifies a max type alignment of 16 bytes on darwin targets, meaning that the builtin nontemporal stores don't correctly align the loads/stores to 32 or 64 bytes when required, resulting in lowering to temporal unaligned loads/stores.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@309382 91177308-0d34-0410-b5e6-96231b3b80d8