[libcxx] Handle AppleClang 9 and 10 in XFAILs for aligned allocation tests

I forgot that those don't behave like Clang trunk, again.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@349427 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed