[X86] Reduce the number of setzero intrinsics to just the set defined by the...

[X86] Reduce the number of setzero intrinsics to just the set defined by the Intel Intrinsics Guide.

We had quite a few for different element sizes of integers sometimes with strange target features attached to them.

We only need a single version for each of _m128i, _m256i, and _m512i with the target feature that first introduced those types.

llvm-svn: 333568