RFR: 8232689: Remove ParCompactionManager::Action enum

[Ivan Walulya]

Hi all,

Please review the removal of unused Enum from the parallel GC. 

Bug: https://bugs.openjdk.java.net/browse/JDK-8232689 <https://bugs.openjdk.java.net/browse/JDK-8232689>
Webrev: http://cr.openjdk.java.net/~lkorinth/ivan/8232689/ <http://cr.openjdk.java.net/~lkorinth/ivan/8232689/>

Testing: Tier 1 - Tier 3

//Ivan