Fix a problem with reference_wrapper in C++03 that was causing counting predicates to fail. Add a test to make sure it works. However, most of the reference_wrapper tests still fail in C++03 mode, due to a lack of decltype. No change there.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@214760 91177308-0d34-0410-b5e6-96231b3b80d8