[X86] Teach selectScalarSSELoad to accept full 128-bit vector loads and the X86ISD::VZEXT_LOAD opcode.

Disable peephole on some of the tests that no longer require it to properly fold scalar intrinsics.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289424 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed