Fix flaky ReplicaTest.testRestore

[Gautam-aman]

testRestore assumed that a non-periodic snapshot task is always scheduled,
which is not guaranteed due to asynchronous scheduling. This caused
intermittent NoSuchElementException failures in CI.

This change makes snapshot triggering retry-safe and consistent with
other snapshot tests, eliminating flakiness.

Fixes #2276

[leekeiabstraction]

Thank you for the PR! Left some comments

[Gautam-aman]

Thanks for the suggestion. I agree centralizing this would be cleaner long-term.
I kept the handling local to this test to keep the fix minimal and avoid changing shared test utilities. Happy to follow up with a refactor PR if preferred.

[leekeiabstraction]

I kept the handling local to this test to keep the fix minimal and avoid changing shared test utilities. Happy to follow up with a refactor PR if preferred.

I had a quick look, it seems ReplicaTest.testRestore() is the only place that calls removeNonPeriodicScheduledTask(). I believe handling the exception within removeNonPeriodicScheduledTask() is cleaner. not removing when queue is already empty is cleaner.

[Gautam-aman]

Thanks for the suggestion. I’ve removed the remaining try/catch and now rely on removeNonPeriodicScheduledTask() to safely handle the empty case.