[X86][SSE] Shuffle mask decode support for zero extend, scalar float/double moves...

[X86][SSE] Shuffle mask decode support for zero extend, scalar float/double moves and integer load instructions

This patch adds shuffle mask decodes for integer zero extends (pmovzx** and movq xmm,xmm) and scalar float/double loads/moves (movss/movsd).

Also adds shuffle mask decodes for integer loads (movd/movq).

Differential Revision: http://reviews.llvm.org/D7228

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227688 91177308-0d34-0410-b5e6-96231b3b80d8