Fix missing import in run_on_app_dump.py

Change-Id: Ic53625464a264d712aa8142f26a8773e051f74f6
diff --git a/tools/utils.py b/tools/utils.py
index 351a038..81f262f 100644
--- a/tools/utils.py
+++ b/tools/utils.py
@@ -104,6 +104,9 @@
   version = os.environ.get(ANDROID_TOOLS_VERSION_ENVIRONMENT_NAME, '28.0.3')
   return os.path.join(getAndroidHome(), 'build-tools', version)
 
+def is_python3():
+  return sys.version_info.major == 3
+
 def Print(s, quiet=False):
   if quiet:
     return