For now we add just two binaries, one with assertions taking the
fast path, one with assertions taking the slow path, and the ability
to run 1 of `REQUIRE(true)`, `REQUIRE_NOTHROW`, `REQUIRE_THROWS`
in a loop.
I also split off a CMake preset which enables more tests than the
basic `simple-tests` preset, but does not enable the most expensive
tests which force recompilation of Catch2 multiple times.
