Improve diagnostic information about errors during class redefinition

The fix https://bugs.openjdk.java.net/browse/JDK-8192936 disable adding/removing of any methods in the class.

Currently, a lot of methods are generated. The logic/names of such methods are also generated and might be not clear for users.
The JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED, JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED are returned in such cases accordingly to spec.

However, it is not clear which methods are exactly added/deleted. It makes sense to improve logging to report names of methods which user tries to add/delete.