Add log to help debug flaky InstallDontKillTest

Because the test flaky cannot be reproduced with device locally,
it's unclear if the CTS checks the file delete too early. Add a log
here to run test in test infra to help to know if the test needs to
extend the waiting time.

Bug: 309806322
Test: manual. Run CTS and check logcat

Change-Id: I1be7b6ce5f6072edea05ded1e164480c0bf33828