Fix operator & detection trait to check for free function overloads as well

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@221395 91177308-0d34-0410-b5e6-96231b3b80d8
Fix rvalue bug in  __has_operator_addressof

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@221398 91177308-0d34-0410-b5e6-96231b3b80d8