[Flakey Tests] A couple of fixes and cleanups

    hbase-rsgroup/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupMajorCompactionTTL.java
     Remove spurious assert. Just before this it waits an arbitrary 10
     seconds. Compactions could have completed inside this time. The spirit
     of the test remains.

    hbase-server/src/main/java/org/apache/hadoop/hbase/master/cleaner/HFileCleaner.java
     Get log cleaner to go down promptly; its sticking around. See if this
     helps with TestMasterShutdown

    hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/FSHLog.java
     We get a rare NPE trying to sync. Make local copy of SyncFuture and see
     if that helps.

    hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncRegionAdminApi.java
     Compaction may have completed when not expected; allow for it.

    hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestBlockEvictionFromClient.java
     Add wait before testing. Compaction may not have completed. Let
     compaction complete before progressing and then test for empty cache.

    hbase-server/src/test/java/org/apache/hadoop/hbase/master/TestMasterShutdown.java
     Less resources.

    hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestDefaultLoadBalancer.java
     Less resources.

    hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestEndToEndSplitTransaction.java
     Wait till online before we try and do compaction (else request is
     ignored)

    hbase-server/src/test/java/org/apache/hadoop/hbase/tool/TestCanaryTool.java
     Disable test that tests for timeout that fails randomly w/ mockito complaint on some mac os
     x's.