[libcxx] [test] Fix Clang -Wunused-local-typedef warnings.

C++11's [hash.requirements] never required these typedefs from users.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@346912 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed