Add BridgeMethodResolver#isJava6VisibilityBridgeMethodPair to
distinguish between (a) bridge methods introduced in Java 6 to
compensate for inheriting public methods from non-public superclasses
and (b) bridge methods that have existed since Java 5 to accommodate
return type covariance and generic parameters.
In the former case, annotations should be looked up from the original
bridged method (SPR-7900). In the latter, the annotation should be
looked up against the bridge method itself (SPR-8660).
As noted in the Javadoc for the new method, see
http://stas-blogspot.blogspot.com/2010/03/java-bridge-methods-explained.html
for a useful description of the various types of bridge methods, as
well as http://bugs.sun.com/view_bug.do?bug_id=6342411, the bug fixed in
Java 6 resulting in the introduction of 'visibility bridge methods'.
Issue: SPR-8660, SPR-7900