Allow sizeof On Generic Type Parameters

[ajbeach]

I just found a note in one of the tests about a feature request. Short version is sizeof(T) does not compile. Here is the example I found.

forall(otype T)
union ByteView {
    T val;
    char bytes[(sizeof(int))]; // want to change to sizeof(T)
};

I did test it with sizeof(T) and it produced an error, but at the same time it feels like an operation that should be allowed. I think the value is already there, just not accessible directly.

[Aaron Moss <a3moss@…>]

In fea3faa:

Strip bodies of generic structs pre-codegen [fixes #18]