Reduce flakyness of CtsAppOpTestCases

It seems that the intent sometimes gets lost in the void; this is likely
from all window operations still completing from the previous test
cases. If we attempt to start the activity again we can reduce the
flakyness while the test will only run for slightly longer than expected.

Test: atest ForegroundModeAndActiveTest --iterations 100
Bug: 229630363
Bug: 229630515
Bug: 229630489
Bug: 229630627
Bug: 229630397
Bug: 229630649
Change-Id: I91803187665dcc055d8516616b9d423ac980d9d9
2 files changed