[x86] Adding support for some missing intrinsics: _castf32_u32, _castf64_u64, _castu32_f32, _castu64_f64

Summary:
Adding support for some missing intrinsics:
_castf32_u32, _castf64_u64, _castu32_f32, _castu64_f64

Reviewers: craig.topper, LuoYuanke, RKSimon, pengfei

Reviewed By: RKSimon

Subscribers: llvm-commits

Patch by yubing (Bing Yu)

Differential Revision: https://reviews.llvm.org/D67212

llvm-svn: 372802