This is kinda messy, because there is no good way to signal to
the compiler that some code uses direct comparison of floating
point numbers intentionally, so instead we have to use diagnostic
pragmas.
We also have to over-suppress the test files, because Clang (and
possibly GCC) still issue warnings from template instantiation
even if the instantion site is under warning suppression, so the
template definition has to be under warning suppression as well.
Closes#2406
These files are not included by the default
`#include <catch2/catch_test_macros.hpp>` path, so that users do
not have to pay for them if they do not use them. Follow up is to
split out the small part of `catch_preprocessor.hpp` used by the
default test macros (AFAIK, it is just `INTERNAL_CATCH_REMOVE_PARENS`
macro), so that it is not included by the default path either.
Also fixes#1892 by providing the missing macros.
