ITS: power down tablet at end of run_all_tests.py

bug: 193717326
Change-Id: I30b78632013e2d5be21f7a9411e6201f55fcd952
diff --git a/apps/CameraITS/tools/run_all_tests.py b/apps/CameraITS/tools/run_all_tests.py
index d5a2b6b..d5d3b06 100644
--- a/apps/CameraITS/tools/run_all_tests.py
+++ b/apps/CameraITS/tools/run_all_tests.py
@@ -603,5 +603,9 @@
 
   logging.info('Test execution completed.')
 
+  # Power down tablet
+  cmd = f'adb -s {tablet_id} shell input keyevent KEYCODE_POWER'
+  subprocess.Popen(cmd.split())
+
 if __name__ == '__main__':
   main()