GRAILS-9908 - Fix bindability of setters

In some cases this was working and in others it was not.  The issue has to do with a reference check that would fail under certain circumstances because of ClassNode redirects.
Merge branch '2.1.x' into 2.2.x

Conflicts:
	grails-web/src/main/groovy/org/codehaus/groovy/grails/web/binding/DefaultASTDatabindingHelper.java