Revert "[libcxx] implement <experimental/simd> declarations based on P0214R7."

This reverts commit r330627.

This causes several bots to freak out.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@330636 91177308-0d34-0410-b5e6-96231b3b80d8
14 files changed