[tests] Skip flaky TestWorkers.test_worker_multiple_traces test case

[brettlangdon]

This test is non-deterministic and will fail for no reason and so should be skipped.

The problem we are having is that this test relies on us being able to correctly time the flush intervals from the writer, which we are unable to do at this time.

If we can tweak the writer internals in a way where we can make it deterministic then we should revive this test case.

[brettlangdon]

of course, now the flaky test passes and another one fails...

[Kyle-Verhoog]

We can probably remove the test altogether, but I'm fine either way. Yay less flakiness 😄

[brettlangdon]

I think keeping it here but skipping is good for two reasons:

1. If we do find a way to make it work we can re-enable, there is probably some value is this test case
2. If we go to write a similar test we can see this skipped test to let us know that this type of test doesn't work right now