Recent work in the doclet has uncovered some stability issues in VisibleMemberMap.

1. The check for whether a method is overridden is non-deterministic in some cases (e.g. diamond inheritance) and depends on HashMap iteration order. Changing the HashMap to a LinkedHashMap yields a consistent result, but not necessarily a correct one.

2. The ClassMember.isEqual method was modified in the fix for JDK-8157000, and probably should not have been. This method is supposed to detect signature-equivalent methods, but code to check isSimpleOverride was added, and should probably be removed.
http://hg.openjdk.java.net/jdk10/master/rev/2ea4edfdef8e#l16.135