Fix has_unique_object_representation after Clang commit r324134.

Clang previously reported an empty union as having a unique object
representation. This was incorrect and was fixed in a recent Clang commit.

This patch fixes the libc++ tests.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@324153 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed