Bug 1097889 - [Settings] The user feedback textbox resets if the screen ...

...is locked
When defining a module dynamically in a test, we should call `testRequire` first because it creates a new context for modules to be defined on. Detail please refer to this file [1].

[1]: https://github.com/mozilla-b2g/gaia/blob/master/apps/settings/test/unit/modules/apn/apn_list_test.js