[libcxx] [test] Add LIBCPP_ASSERT_NOEXCEPT/LIBCPP_ASSERT_NOT_NOEXCEPT, remove an unused variable.
test/support/test_macros.h
For convenience/greppability, add macros for libcxx-specific static_asserts about noexceptness.
(Moving the definitions of ASSERT_NOEXCEPT/ASSERT_NOT_NOEXCEPT isn't technically necessary
because they're macros, but I think it's better style to define stuff before using it.)
test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp
There was a completely unused TrackedCallable obj;.
apply() isn't depicted with conditional noexcept in C++17.
test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp
Now that we have LIBCPP_ASSERT_NOEXCEPT, use it.