New OnceUx Test Class CompanionAdTestCase.java

##Rationale
Now that Companion Ads have been implemented into the Sample App, It's time for tests.
##Changed Files
**CompanionAdTestCase.java**
* New utility methods
    * *companionCheck* finds the companion ad based on the companion ad frame's resource id
    * *toCompanionAdCheck(int msec)* navigates to the next ad break, then performs *companionCheck*. It returns the results of *companionCheck*.
    * *toEndOfAdBreak* navigates to the end of an ad break, hides the seek controls, and then performs *companionCheck*. It returns the results of *companionCheck*.
* New tests
    * **testCompanionAd** navigates through the video using *toCompanionAdCheck* and *toEndOfAdBreak*. After the start of each ad break, it asserts that the companion ad is present.
    * **testCompanionAdLink** clicks on a companion ad and tests for the presence of the browser url the click is meant to link to
    * **testCompanionAdVanish** navigates through the video using *toCompanionAdCheck* and *toEndOfAdBreak*, checking after the end of each ad break for the presence of a companion ad. It asserts that *toEndOfAdBreak* will return false for each ad break.
Programmatic seeking is not available with UiAutomator because of its black box nature, and programming clicking and dragging on the seek bar would take hours to determine to which pixel the playhead should be dragged. I am currently waiting on a bug fix (AND-13 on Jira) that would allow presses of the fast forward button to functionally skip forward through content, waiting through the Ad Breaks will always have to happen (once again, due to UiAutomator's black box nature).  

I considered consolidating both testCompanionAd and testCompanionAdVanish to shorten the length of the test time, but I didn't want to have a test with six asserts that was testing multiple things. If that's preferable to waiting 7 minutes for the tests to finish, I will change it.