Incorrect `parameterSlots` and `returnSlots` for some methods in `functionDebugData` about solidity

[cameel]

Thanks for the report! I can confirm that this still happens on 0.8.25. And not only for shanghai. At first I thought it could be somehow related to PUSH0, but does not seems so.

I think that this may be the culprit:

solidity/libsolidity/codegen/CompilerContext.cpp

Lines 582 to 589 in b61c2a9

	size_t params = 0;
	size_t returns = 0;
	if (auto const* function = dynamic_cast<FunctionDefinition const*>(&_declaration))
	{
	FunctionType functionType(*function, FunctionType::Kind::Internal);
	params = CompilerUtils::sizeOnStack(functionType.parameterTypes());
	returns = CompilerUtils::sizeOnStack(functionType.returnParameterTypes());
	}

The assumption there may have been that only builtin functions do not have definitions. That's not true - getters don't have them either. Still, just assuming zero does not seem to make much sense for builtins either, so I suspect that there could be other cases affected by this.