Allow skipping optional tests for optional methods in plugins

[Shaddoll]

What changed?

• Allow user to skip GetOrphanTasksTest and ScanHistoryTest

Why?

• Database supporting TTL doesn't need to implement GetOrphanTasks
• GetAllHistoryTreeBranches doesn't work for sharded SQL

How did you test it?
existing tests

Potential risks

Release notes

Documentation Changes

[coveralls]

Pull Request Test Coverage Report for Build 42fb267c-c1d8-4896-bc5d-6e343603e392

• 0 of 6 (0.0%) changed or added relevant lines in 2 files are covered.
• 102 unchanged lines in 11 files lost coverage.
• Overall coverage decreased (-0.06%) to 59.958%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
common/persistence/persistence-tests/historyV2PersistenceTest.go	0	3	0.0%
common/persistence/persistence-tests/matchingPersistenceTest.go	0	3	0.0%

Files with Coverage Reduction	New Missed Lines	%
service/history/queue/timer_queue_processor_base.go	1	78.6%
common/membership/rpServiceResolver.go	2	73.58%
common/task/weightedRoundRobinTaskScheduler.go	2	89.64%
service/history/task/fetcher.go	2	77.18%
service/matching/taskListManager.go	2	74.72%
service/history/task/transfer_active_task_executor.go	4	69.73%
common/task/fifoTaskScheduler.go	5	82.47%
common/persistence/nosql/nosqlplugin/cassandra/tasks.go	14	72.8%
common/persistence/cassandra/cassandraTaskPersistence.go	16	58.02%
common/persistence/cassandra/cassandraPersistence.go	23	50.62%

Totals
Change from base Build 8385cc09-aa2d-433f-9f36-97eb9c957446:	-0.06%
Covered Lines:	90255
Relevant Lines:	150530

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💛 - Coveralls