Decouple StateBuilder from TaskGenerator

[vytautas-karpavicius]

What changed? Decoupled StateBuilder from TaskGenerator by moving task generation to Replicate<...> functions on mutable state. Task generation is needed on both active and passive side, so there is no need to call them separately. There were only a few places where active/passive side differs slightly. For them we can simply pass additional flag modifying that behavior. In particular, more attention is needed for:

• ReplicateWorkflowExecutionStartedEvent will GenerateDelayedDecisionTasks only for passive side. Active side does that separately during AddFirstDecisionTaskScheduled.
• After rebuilding GenerateActivityTimerTasks/GenerateUserTimerTasks was called. This can be skipped here, and instead call when closing a transaction. Previously it was not done due to transactionPolicy == TransactionPolicyPassive, now this is removed. And they will be generated for both active/passive cases.

Why?

• Reduced tech debt as indicates by // TODO merge active & passive task generation.
• This also decouples StateBuilder which makes it possible to further refactor and simplify.
• Task generation is more centralized.

How did you test it? Existing tests

Potential risks

Release notes

Documentation Changes

[coveralls]

Pull Request Test Coverage Report for Build 01845b66-af76-468b-b785-8fd9f14ff9ae

• 62 of 71 (87.32%) changed or added relevant lines in 3 files are covered.
• 118 unchanged lines in 16 files lost coverage.
• Overall coverage decreased (-0.06%) to 57.253%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
service/history/execution/mutable_state_decision_task_manager.go	9	12	75.0%
service/history/execution/mutable_state_builder.go	37	43	86.05%
<!--	Total:	62	71

Files with Coverage Reduction	New Missed Lines	%
common/types/shared.go	1	41.66%
service/history/execution/mutable_state_builder.go	1	68.81%
common/task/parallelTaskProcessor.go	2	92.75%
common/util.go	2	52.44%
service/history/execution/mutable_state_util.go	2	36.14%
service/history/task/transfer_active_task_executor.go	2	72.15%
service/matching/taskListManager.go	2	75.87%
common/persistence/statsComputer.go	3	93.57%
common/persistence/serialization/parser.go	4	62.41%
common/persistence/serialization/thrift_decoder.go	4	53.06%
<!--	Total:	118

Totals
Change from base Build 018451f7-faad-49b3-945b-1604e2186a55:	-0.06%
Covered Lines:	85070
Relevant Lines:	148586

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💛 - Coveralls