[PATCH] Fix PR libstdc++/68739 on hpux

[Jonathan Wakely]

On 18/02/17 09:45 -0500, John David Anglin wrote:
>The attached change fixes the fails noted in PR 68730.  Okay for trunk?

No, the whole point of that test type is to check that the type can be
declared as a constexpr variable.

The problem is that types like std::mutex can't be constexpr for some
targets:

#ifdef __GTHREAD_MUTEX_INIT
    constexpr
#endif
    mutex() noexcept = default;

We need to disable the tests for those targets, not weaken the tests
so they don't check the condition for any targets.