fix: remove Thread.sleep() from DefaultWorkQueueTest

[sarveshkaushal]

Notes

This change removes the Thread.sleep() dependency on the DefaultWorkQueueTest and replaces it with explicit thread synchronization.. This is related to issue #1223

Testing

Ran mvn install from project root and build completed successfully.

[kubernetes-prow]

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[sarveshkaushal]

/assign @brendandburns
/assign @yue9944882

[brendandburns]

I think there are a lot of whitespace changes that make this hard to review because it makes the diff much bigger than it needs to be.

Please minimize the diff and then I can do a real review.