ITS: change python3 --> python in tools/run_all_tests.py

bug: 215507536
Change-Id: Ia6b14c2627833f603e3675ac79b33bbe65ad4c00
diff --git a/apps/CameraITS/tools/run_all_tests.py b/apps/CameraITS/tools/run_all_tests.py
index 54b5b48..d9b0afc 100644
--- a/apps/CameraITS/tools/run_all_tests.py
+++ b/apps/CameraITS/tools/run_all_tests.py
@@ -504,13 +504,13 @@
         # Handle repeated test
         if 'tests/' in test:
           cmd = [
-              'python3',
+              'python',
               os.path.join(os.environ['CAMERA_ITS_TOP'], test), '-c',
               '%s' % new_yml_file_name
           ]
         else:
           cmd = [
-              'python3',
+              'python',
               os.path.join(os.environ['CAMERA_ITS_TOP'], 'tests', s, test),
               '-c',
               '%s' % new_yml_file_name