[builtins] Use Interlocked* intrinsics for atomics on MSVC

Tested on MSVC 2013, 2015 and 2017 targeting X86, X64 and ARM.

This fixes building emutls.c for Windows for ARM (both with clang
which don't need these atomics fallbacks at all, but just failed
due to the immintrin.h include before, and with MSVC).

Differential Revision: https://reviews.llvm.org/D36071

llvm-svn: 309974