Add a new option in recovery menu to test the background texts

Add a new option "Run locale test" to check the background text
images (i.e. texts for "erasing", "error", "no_command" and "installing"
with different locales.)

Use volume up/down button to cycle through all the locales embedded in
the png file, and power button to go back to recovery main menu.

Test: Run locale test with bullhead.
Change-Id: Ib16e119f372110cdb5e611ef497b0f9b9b418f51
diff --git a/device.h b/device.h
index 639e2bf..74745b3 100644
--- a/device.h
+++ b/device.h
@@ -66,6 +66,7 @@
     VIEW_RECOVERY_LOGS = 9,
     MOUNT_SYSTEM = 10,
     RUN_GRAPHICS_TEST = 11,
+    RUN_LOCALE_TEST = 12,
   };
 
   // Return the list of menu items (an array of strings, NULL-terminated). The menu_position passed