[PATCH] D21098: [libcxx] [test] Replace __cplusplus comparisons with TEST_STD_VER and __has_feature with TEST_HAS_FEATURE.

[Stephan T. Lavavej via cfe-commits]

[Eric Fiselier] 
> Please change the `TEST_HAS_FEATURE(XXX)` into `TEST_STD_VER >= 11` for the following C++11 features:
> - `cxx_noexcept`
> - `cxx_atomic`
> - `cxx_access_control_sfinae`
> Also if the entire test is wrapped in a `TEST_HAS_FEATURE(XXX)` please 
> translate that into a `// UNSUPPORTED: c++98, c++03` comment at the top of the file.

Sure. Would you like cxx_attributes and/or cxx_strong_enums to receive the same treatment?

STL