Attempt to fix aligned allocation configuration under clang-cl

When we're using clang-cl and Microsoft's runtime implementation,
we don't provide align_val_t or aligned new/delete ourselves.

This patch updates the _LIBCPP_HAS_NO_ALIGNED_ALLOCATION macro
to reflect this.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@343441 91177308-0d34-0410-b5e6-96231b3b80d8