The PMOVZXWD family of functions had patterns extends narrow vector types to wide...

The PMOVZXWD family of functions had patterns extends narrow vector types to wide vector types.
It had patterns for zext-loading and extending. This commit adds patterns for loading a wide type, performing a bitcast,
and extending. This is an odd pattern, but it is commonly used when writing code with intrinsics.

rdar://11897677

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163995 91177308-0d34-0410-b5e6-96231b3b80d8