[modules] Mark __wmmintrin_pclmul.h/__wmmintrin_aes.h as textual

Summary:
Since clang r332929 these two headers throw errors when included from somewhere else than their wrapper header. It seems marking them as textual is the best way to fix the builds.

Fixes this new module build error:
    While building module '_Builtin_intrinsics' imported from ...:
    In file included from <module-includes>:2:
    In file included from lib/clang/7.0.0/include/immintrin.h:54:
    In file included from lib/clang/7.0.0/include/wmmintrin.h:29:
    lib/clang/7.0.0/include/__wmmintrin_aes.h:25:2: error: "Never use <__wmmintrin_aes.h> directly; include <wmmintrin.h> instead."
    #error "Never use <__wmmintrin_aes.h> directly; include <wmmintrin.h> instead."

Reviewers: rsmith, v.g.vassilev, craig.topper

Reviewed By: craig.topper

Subscribers: craig.topper, cfe-commits

Differential Revision: https://reviews.llvm.org/D47277

llvm-svn: 333123