Fix #4775: SpotlightFragmentTest is very flaky

[JishnuGoyal]

Explanation

fixes #4775

This PR was created to investigate why 2 tests mentioned here were so flaky and fix these issues. From what I found, it seems that the problem occurs in sequencing while adding spotlight targets:

checkNotNull(activity.getSpotlightFragment()).requestSpotlight(firstSpotlightTarget)
checkNotNull(activity.getSpotlightFragment()).requestSpotlight(secondSpotlightTarget)

The addition of targets probably lead to a race condition? I haven't really gotten as deep as to debug it though, but I assumed my speculation was correct, and an easy fix was to add testCoroutineDispatchers.runCurrent() between these two lines.

Essential Checklist

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[BenHenning]

Thanks @JishnuGoyal. This seems reasonable. Have you run the tests ~100 times to verify they are no longer flaky? This is usually really straightforward with Bazel by running the whole test suite with the runs_per_test flag set.

[JishnuGoyal]

Hi @BenHenning, I ran the tests for a 100 times and it seems like they all passed (PTAL at the result):

[BenHenning]

Thanks @JishnuGoyal! This LGTM.