[HBASE-9704] Fix the HTableClientScanner when the scan is done and the region is done.

Author: manukranthk

Summary: Result[] being null marks end of scan and being [] marks end of region. But in case when both happen, we progress to the next region, which is pointless.

Test Plan: Unit test

Reviewers: rshroff, gauravm

Reviewed By: gauravm

CC: hbase-eng@, daviddeng, gauravm

Differential Revision: https://phabricator.fb.com/D1281576

Task ID: 4158431

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1588535 13f79535-47bb-0310-9956-ffa450edef68
[master] Fix the problem of scanning over stopRow

Author: daviddeng

Summary:
Checking of end-of-scan after get the results in  `nextRow`
Add a testcase just for the bug.

Test Plan: `TestHTableClientScanner`

Reviewers: manukranthk, rshroff, gauravm

Reviewed By: manukranthk

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D1284277

Task ID: 4158431

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1588536 13f79535-47bb-0310-9956-ffa450edef68