[tools] Use a flag to ensure that we keep logs on timeout

R=machenbach@chromium.org

Bug: chromium:891314
Change-Id: Iaab09ac543b0928f6a81275f529df73949693c83
Reviewed-on: https://chromium-review.googlesource.com/c/1276425
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56630}

tools/testrunner/local/android.py

@@ -167,6 +167,7 @@ class _Driver(object):
             env=env,
             timeout=timeout,
             retries=0,
+            ensure_logs_on_timeout=True,
         )
         return '\n'.join(output)
       except device_errors.AdbCommandFailedError as e: