[Chromium] Return an accurate exit code when running Android suites, and wait after restarting adb as root
https://bugs.webkit.org/show_bug.cgi?id=103065

Reviewed by Dirk Pranke.

This addresses two further reliability issues in the Android test running
scripts. Firstly, the run_tests.py script needs to have the --exit_code
argument passed in order to return non-zero codes, which we need for the
build master to distinguish failures from successful runs.

Secondly, it modifies the layout test runner to briefly wait (through
the wait-for-device command) after requesting a device to switch to root
mode. Without this waiting period, commands might get lost and thereby
unexpectedly fail.

* Scripts/run-api-tests:
* Scripts/run-chromium-webkit-unit-tests:
* Scripts/webkitpy/layout_tests/port/chromium_android.py:
(ChromiumAndroidDriver._setup_test):
(ChromiumAndroidDriver._restart_adb_as_root):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@135552 268f45cc-cd09-0410-ab3c-d52691b4dbfc