V3. Add a zero-arg constructor unit test.
Merge branch 'trunk' into YARN-2944-SCMStore-reflection
Add null check to InMemorySCMStore#serviceStop.
rename SCMStoreBaseTest
Merge branch 'trunk' into YARN-2944-SCMStore-reflection
Merge branch 'YARN-2944-SCMStore-reflection' into sharedcache-8-YARN-2203-ui