MethodDelegate: allow for swapping value type with object, and allow ref for arg 0 on value type

[Eddio0141]

This changes AccessTools.MethodDelegate to let you use object where a value type exists

Also lets you use ref for the first argument with value types, since currently you can't mutate structs from dynamic methods generated when open instance without boxing, so this lets you use delegates such as void MyFunc(ref UnityEngine.Resolution res);

[pardeike]

That’s nice work!

[pardeike]

Maybe you can add some tests too?

[Eddio0141]

Thanks! Also sorry for the messy commits, I've squashed them to two commits to try make it clean
I've added 2 tests which should test the exact code, it is all done now and should be passing

Also I just realised, this fix would only apply for virtualCall: false, since delegates is incompatible normally, and this fixes just the dmd to handle these things