[Clang][X86] Change X86 cast intrinsics to use __builtin_nondeterministic_value

The following intrinsics are currently implemented using a shufflevector with
an undefined mask, this is however incorrect according to intel's semantics for
undefined value which expect an unknown but consistent value.

With __builtin_nondeterministic_value we can now match intel's undefined value.

Differential Revision: https://reviews.llvm.org/D143287