getAllImportedRules uses HashSet, making getDelegatedRules order non-deterministic

[alexofortune]

As in title.

This basically makes generated .java files and thus .class files non-deterministic. This seems to at least make the Apache Hive's grammar file compile in a different way every time.

Best way to handle this is probably to replace HashSet with TreeSet and making the relevant methods return OrderedSet<> instead of Set<>.