Get rid of mutex in matching/liveness and reduce test duration

[taylanisikdemir]

What changed?

• Replaced mutex with atomic
• Updated Stop() to wait for background goroutine completion
• Added a new log to distinguish between regular tasklist stop vs liveness originated tasklist stop
• Removed time argument from markAlive because only time.Now is passed
• Reduced test duration from 8 sec to 2s

Why?
Just applying some best practices to improve things step by step.

How did you test it?

go test -timeout 60s -run ^TestLivenessSuite$ github.com/uber/cadence/service/matching -count=100 -v -race

[codecov]

Codecov Report

Merging #5917 (b0b842b) into master (e98ce90) will decrease coverage by 0.27%.
The diff coverage is 96.55%.

❗ Current head b0b842b differs from pull request most recent head 46e2707. Consider uploading reports for the commit 46e2707 to get more accurate results

Additional details and impacted files

Files	Coverage Δ
service/matching/taskListManager.go	72.31% <100.00%> (+0.36%)	⬆️
service/matching/liveness.go	94.59% <95.45%> (-0.86%)	⬇️

... and 13 files with indirect coverage changes

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[coveralls]

Pull Request Test Coverage Report for Build 018ef271-caca-4f0c-bb43-d164077df25c

Details

• 29 of 29 (100.0%) changed or added relevant lines in 2 files are covered.
• 41 unchanged lines in 9 files lost coverage.
• Overall coverage decreased (-0.003%) to 67.539%

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Files with Coverage Reduction	New Missed Lines	%
service/history/queue/timer_queue_processor_base.go	1	77.62%
service/matching/liveness.go	1	95.56%
common/task/weighted_round_robin_task_scheduler.go	2	88.56%
common/task/fifo_task_scheduler.go	2	87.63%
service/history/execution/mutable_state_util.go	2	78.52%
common/persistence/historyManager.go	2	66.67%
service/history/queue/timer_gate.go	3	95.83%
service/matching/taskListManager.go	4	79.9%
service/history/execution/mutable_state_task_refresher.go	24	57.28%

Totals
Change from base Build 018ef25f-2676-4198-8971-594ae20e6cd1:	-0.003%
Covered Lines:	98857
Relevant Lines:	146371

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💛 - Coveralls