Fix & test qrep pause/unpause

[serprex]

As is apt to happen when adding tests, also fix pause/unpause for qrep/xmin

1. waitForNewRows would prevent pausing; use a selector to wait on signals while waiting on new rows while waiting on context cancelation
2. CurrentFlowStatus wasn't being set to RUNNING when exiting from PAUSED

As an aside, it turns out all the qrep/xmin tests are doing InitialCopyOnly besides this new test

Also remove DisableWaitForNewRows because it's unused & is meant to diverge testing from reality

[serprex]

Failures here are showing that temporal testsuite is not suitable for integration testing because ContinueAsNew isn't handled

temporalio/sdk-go#805

Looks like even children workflows return continue as new error instead of behaving as they should

[iskakaushik]

@serprex is there a way to prevent INFO logs from showing up in tests?

***"time":"2024-03-04T15:06:03.6158228Z","level":"INFO","msg":"Sent Standby status message. processed 0 rows","Namespace":"default","TaskQueue":"peer-flow-task-queue","WorkerID":"4459@vm8n9339@","ActivityID":"11","ActivityType":"MaintainPull","Attempt":1,"WorkflowType":"SyncFlowWorkflow","WorkflowID":"sync-flow-test_simple_schema_changes_bq_idwud1dh_20240304150318-f97680e0-504d-438e-8b02-372c948200e3","RunID":"9b958103-daaa-48ad-aa90-0f4093f79338","deploymentUid":""***

[serprex]

Yes, we'd have to pass a log level when invoking peer-flow

Will do so in a separate PR

(I tried to avoid some issue by using go test without -v so that it'd buffer logs & spit them out in chunks. The ideal would be for peer-flow to run in another step in background, but alas, github actions don't handle stdout continuing to flow to a finished step)