This ensures that emmintrin.h is included with clang-cl. Otherwise, errors like
this occur:
.../absl/container/internal/raw_hash_set.h(536,8): error: unknown type name '__m128i'
inline __m128i _mm_cmpgt_epi8_fixed(__m128i a, __m128i b) {
This aligns the include ifdef guards and the guards that use the provided APIs.
The includes are also reordered, so they appear after the config header which
provides the internal macro values.
PiperOrigin-RevId: 456530271
Change-Id: I86dfd0022fd06fe7aa132138ec4d1bd14a86ba84
