remove old metrics wrappers and use new generated metered wrappers

[3vilhamster]

What changed?
Switched to generated metered wrappers.
Previously, I've introduced metered wrappers for all persistence managers and verified that the behavior of these methods didn't change.
So it is safe to switch to them and remove the old untested file.

Why?
Improve test coverage and remove unused code.

How did you test it?
Unit tests to ensure that behaviour is the same between old metered clients and new one.

Potential risks
Logs/metrics could be affected, though with unit tests it is very unlikely.

Release notes

Documentation Changes

[coveralls]

Pull Request Test Coverage Report for Build 018e0ef0-e611-45e8-b1fe-a587e7133718

Details

• 10 of 11 (90.91%) changed or added relevant lines in 2 files are covered.
• 65 unchanged lines in 10 files lost coverage.
• Overall coverage increased (+0.1%) to 63.088%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
host/onebox.go	2	3	66.67%

Files with Coverage Reduction	New Missed Lines	%
common/persistence/executionManager.go	2	78.59%
common/persistence/statsComputer.go	2	93.57%
common/task/weighted_round_robin_task_scheduler.go	2	89.05%
service/history/execution/mutable_state_util.go	2	37.63%
service/history/task/transfer_standby_task_executor.go	2	85.77%
service/matching/taskReader.go	2	84.88%
service/history/shard/context.go	9	66.84%
service/history/execution/context.go	14	68.05%
service/history/execution/mutable_state_task_refresher.go	14	62.34%
common/persistence/sql/sql_execution_store.go	16	79.15%

Totals
Change from base Build 018e0d82-79ea-4513-9f5b-be2bbdc6e60f:	0.1%
Covered Lines:	92530
Relevant Lines:	146667

---

💛 - Coveralls