GROOVY-8283: field hides getter of super class (not interface)

[eric-milles]

For the dynamic side of 8283, field can be selected in MetaClassImpl. If access method is declared by an interface, the interface method is the one indexed so must be considered pervasive in the type hierarchy (cannot be safely hidden). Not sure if this kind of name hiding should be extended to inner classes; hopefully the commit is enough of a first step to determine if this protocol should be changed or left alone.

@blackdrag @paulk-asert

TODO:

• setter method
• STC selection of field vs method (verify what StaticTypeCheckingVisitor does vs MetaClassImpl)
• static compiler classgen -- I think it currently selects the method

https://issues.apache.org/jira/browse/GROOVY-8283

[eric-milles]

c880517 might be good to go in on its own. There is some confusion between sender and theClass because MetaClassImpl uses theClass for sender in the get and set variants that accept only receiver and name.