unit test flake: Test_Sync_Result_Correct_Root_Update_Root_During

[marun]

Unit test flake has been occurring since #3106 merged a couple of weeks ago:

panic: test timed out after 2m0s
running tests:
	Test_Sync_Result_Correct_Root_Update_Root_During (1m34s)
...
	/home/runner/work/avalanchego/avalanchego/x/sync/manager.go:213 +0x504
FAIL	github.com/ava-labs/avalanchego/x/sync	120.505s

• 10/01/2024 https://github.com/ava-labs/avalanchego/actions/runs/11131823518/job/30934288345
• 10/12/2024 https://github.com/ava-labs/avalanchego/actions/runs/11301634174/job/31436319219
• 10/16/2024 https://github.com/ava-labs/avalanchego/actions/runs/11369775910/job/31628064127
• 10/16/2024 https://github.com/ava-labs/avalanchego/actions/runs/11372830050/job/31638039498

[github-actions]

This issue has become stale because it has been open 60 days with no activity. Adding the lifecycle/frozen label will cause this issue to ignore lifecycle events.