This change fixes the frontend tests to make them run on Java 8, by
replacing HashMap with LinkedHashMap and HashSet with LinkedHashSet
where needed.
To test this I ran the frontend tests using both Oracle Java 7 and
Oracle Java 8 and made sure they passed. I also verified that the tests
pass with OpenJDK 7.
Change-Id: Iad8e1dccec3a51293a109c420bd2b88b9d1e0625
Reviewed-on: http://gerrit.cloudera.org:8080/7073
Reviewed-by: Lars Volker <lv@cloudera.com>
Tested-by: Impala Public Jenkins
ae5a8770ee