* Remove ModuleCompiledFunction
The same information can be retrieved using
ctx.compiled_code().unwrap().code_info().total_size
In addition for Module implementations that don't immediately compile the
given function there is no correct value that can be returned.
* Don't give anonymous functions and data objects an internal name
This internal name can conflict if a module is serialized and then
deserialized into another module. It also wasn't used by any of the
Module implementations anyway.
* Allow serializing all cranelift-module data structures
This allows a Module implementation to serialize it's internal state and
deserialize it in another compilation session. For example to implement
LTO or to load the module into cranelift-interpreter.
* Use expect