Custom objects returned by modules must be subclass of ModuleObject and
have the state argument in its methods.
Add MutableModuleObject base class for objects that needs to be deep
copied on assignation.
Also, remove the possibility of passing in a compiler instance to
min_driver_version. This is because the NVCC compiler instance is,
as of CUDA Toolkit 11.0, no longer guaranteed to be versioned
identically to the toolkit itself.
D lang compilers have an option -release (or similar) which turns off
asserts, contracts, and other runtime type checking. This patch wires
that up to the b_ndebug flag.
Fixes#7082