Bug 867885 - Write a test for bug 867649: Test that SMS app acquires CPU wake lock after receiving system message and then releases it after displaying a notification to the user r=gnarf

* Moved the wake lock and notification helper mocks to /shared
* added lots of mocks, some very basic, some in /shared
* added tests for the actibity handler
(cherry picked from commit 933fe64315ff7445aa619b16bf08832f9b5faaf0)