[master] Fix bugs in MemStoreFlusher

Author: daviddeng

Summary:
Use `ScheduledThreadPoolExecutor`
Change some logic
Add `IHRegion` and `IHRegionServer` interfaces.
Add testcase

Test Plan:
`TestMemStoreFlusher`
`TestRegionServerOnlineConfigChange`
`TestPerColumnFamilyFlush.testFlushingWhenLogRolling`

Reviewers: liyintang, gauravm, aaiyer, khadkevich, manukranthk

Reviewed By: manukranthk

CC: hbase-eng@, fan, elliott

Differential Revision: https://phabricator.fb.com/D1264374

Task ID: 4114747

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1586735 13f79535-47bb-0310-9956-ffa450edef68
[master] Add sleep for restart ThriftServerRunner

Author: daviddeng

Summary: Add a sleep in `catch` block

Test Plan: `TestThriftMutationAPI`

Reviewers: manukranthk, rshroff

Reviewed By: manukranthk

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D1268413

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1586736 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-10959] Build sources for tests

Author: manukranthk

Summary: Adds maven execution to build sources jar for tests as well.

Test Plan: mvn -DskipTests package

Reviewers: adela, liyintang, nileema

Reviewed By: adela

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D1268802

Task ID: 4027020

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1586737 13f79535-47bb-0310-9956-ffa450edef68