Current state.
cct_module scripts set the following settings:
-XX:+UnlockExperimentalVMOptions
-XX:+UseCGroupMemoryLimitForHeap
-XX:+UseParallelOldGC - this one gets removed by broker scripts
-XX:MinHeapFreeRatio=10
-XX:MaxHeapFreeRatio=20
-XX:GCTimeRatio=4
-XX:AdaptiveSizePolicyWeight=90
-XX:MaxMetaspaceSize=100m
-XX:+ExitOnOutOfMemoryError

on startup of the broker. The following are dynamically set by artemis:
-XX:+PrintClassHistogram
-XX:+UseG1GC
-XX:+AggressiveOpts
-XX:+UseFastAccessorMethods
-Xms512M
-Xmx2G
-Dhawtio.realm=activemq
-Dhawtio.offline="true"
-Dhawtio.role=admin
-Dhawtio.rolePrincipalClasses=...
-Djolokia.policyLocation=...
-Djon.id=amq"

We should:
1) remove the UseG1GC and leave in the UseParallelOldGC.
2) remove Xms and Xms