This piece of code faces the following issues/challenges:

1. The expected debug log line may be emitted while wait_until times out. Successive retries miss the log line because assert_debug_log does not look into the past.
2. lambda: not self.can_find_proof_in_poll(...) is not expected to return immediately once the proof has finalized/stalled, making #1 worse.
3. The retry loop may retry for reasons unrelated to its intended purpose.
4. In the stalled proof check, the timeout is insufficient for TSAN.

This patch fixes all of these issues by replacing the complex retry loop with a dumb for loop that resides inside of the assert_debug_context. This ensures that the log will always be captured. The tradeoff is multiple calls to can_find_proof_in_poll, which gives a small hit to test timing (a few seconds in total).