Run ClangTidy tests in all C++ language modes

Summary:
I inspected every test and did one of the following:

- changed the test to run in all language modes,

- added a comment explaining why the test is only applicable in a
  certain mode,

- limited the test to language modes where it passes and added a FIXME
  to fix the checker or the test.

Reviewers: alexfh, lebedev.ri

Subscribers: nemanjai, kbarton, arphaman, jdoerfert, lebedev.ri, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62125

llvm-svn: 361131