It won't be enough to fix cross in all cases, but it is in at least
one: pywayland. I've only made the change in cases I'm confident it's
correct, as it would be wrong to change this when python.interpreter
is used in wrappers, and possibly when it's used for running tests.
checkInputs used to be added to nativeBuildInputs. Now we have
nativeCheckInputs to do that instead. Doing this treewide change allows
to keep hashes identical to before the introduction of
nativeCheckInputs.
