Missing InnerClasses attribute check

Section 4.7.6 of the JVM Spec contains the following:

If a class file has a version number that is 51.0 or above, and has an InnerClasses attribute in its attributes table, then for all entries in the classes array of the InnerClasses attribute, the value of the outer_class_info_index item must be zero if the value of the inner_name_index item is zero.

This check is missing from the JVM.