Always wait for session end in PrinterDiscoverySessionLifecycleTest

Otherwise we sometimes deal with the session getting restarted in the
middle of the test, sometimes not. This causes flakiness.

Fixes: 153951939
Test: atest --rerun-until-failure 100 android.print.cts.PrinterDiscoverySessionLifecycleTest#startPrinterDiscoveryWithHistoricalPrinters
Change-Id: I8cd2e457f31d13e1aa017d7bdef227d44109fbf5
1 file changed