[libcxx] [test] Make vector.bool/construct_default.pass.cpp more portable.

[STL_MSFT]

Summary

Make vector.bool/construct_default.pass.cpp more portable.

vector<bool>'s default ctor and allocator ctor aren't depicted as noexcept in the Working Paper. We're already directly including test_macros.h, so use LIBCPP_STATIC_ASSERT.

[EricWF]

The fact that they are not noexcept in the working paper seems like an oversight. Is there a reason your vector<bool> default constructor can't be noexcept?

[STL_MSFT]

Nah, they can totally be noexcept like the primary template. Usually we don't strengthen beyond the WP, but the wording is so clearly defective here, I'll go ahead and do this. No test changes necessary now.