[InstCombine] Added vector demanded bits support for SSE4A EXTRQ/INSERTQ instructions

The SSE4A instructions EXTRQ/INSERTQ only use the lower 64-bits (or less) for many of their input vector operands and all of them have undefined upper 64-bits results.

Differential Revision: http://reviews.llvm.org/D12680

llvm-svn: 247934