Fix some flaky int tests

[cicoyle]

Trying to fix some flakiness with:

• reminders/scheduler/unregister
• binding appready - cant find the build link again, but the binding call was starting as 1, so Im starting it explicitly as 0 for the test at the start
• pubsub/grpc/appready
• slow unit test for windows: healthtest for pkg/actors/health

[cicoyle]

I can't repro this unit test failure. This PR addresses all others I've seen thus far