[clang-tidy] Add a check for RAII temporaries.

Summary:
This tries to find code similar that immediately destroys
an object that looks like it's trying to follow RAII.
  {
    scoped_lock(&global_mutex);
    critical_section();
  }

This checker will have false positives if someone uses this pattern
to legitimately invoke a destructor immediately (or the statement is
at the end of a scope anyway). To reduce the number we ignore this
pattern in macros (this is heavily used by gtest) and ignore objects
with no user-defined destructor.

Reviewers: alexfh, djasper

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4615