bluetooth: python3 migration for bluetooth_TurnOnOffUI test

BUG=b:200108562
TEST=Pass the client-side bluetooth_TurnOnOffUI test.

Change-Id: I9f525777323b5e324c1264508e8f2ea2a02b70f5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/3168514
Tested-by: Shyh-In Hwang <josephsih@chromium.org>
Commit-Queue: Shyh-In Hwang <josephsih@chromium.org>
Reviewed-by: Shijin Abraham <shijinabraham@google.com>
diff --git a/client/site_tests/bluetooth_TurnOnOffUI/bluetooth_TurnOnOffUI.py b/client/site_tests/bluetooth_TurnOnOffUI/bluetooth_TurnOnOffUI.py
index 0e04077..0b33705 100644
--- a/client/site_tests/bluetooth_TurnOnOffUI/bluetooth_TurnOnOffUI.py
+++ b/client/site_tests/bluetooth_TurnOnOffUI/bluetooth_TurnOnOffUI.py
@@ -1,3 +1,4 @@
+# Lint as: python2, python3
 # Copyright 2018 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
@@ -37,7 +38,7 @@
         """Autotest cleanup function"""
         if self._GSC:
             keyvals = self._GSC.get_memory_difference_keyvals()
-            for key, val in keyvals.iteritems():
+            for key, val in keyvals.items():
                 self.output_perf_value(
                     description=key,
                     value=val,
diff --git a/client/site_tests/bluetooth_TurnOnOffUI/control b/client/site_tests/bluetooth_TurnOnOffUI/control
index 0f565bd..91251b8 100644
--- a/client/site_tests/bluetooth_TurnOnOffUI/control
+++ b/client/site_tests/bluetooth_TurnOnOffUI/control
@@ -11,6 +11,8 @@
 TEST_CATEGORY = "Functional"
 TEST_CLASS = "Bluetooth"
 TEST_TYPE = "client"
+PY_VERSION = 3
+
 DOC = """
 Go to status tray and turn on/off BT
 Command to execute is