Refactoring CompanionAdTestCase.java

##Rationale
It was suggested by @BCjwhisenant that my next move be to refactor **CompanionAdTestCase.java**, as, while it did work correctly, it was a little clunky and difficult to read and as someone who is still a beginner, learning to refactor code is an important skill.

##Changed Files
**OnceUxUiAutomatorBase.java**
* Changed *msecToPreroll* to 8000 to allow for less fails when the video takes too long to load.

**CompanionAdTestCase.java**
* Consolidated *testCompanionAd* and *testCompanionAdVanish* into one test
  * moved asserts to utility methods waitForCompanionAdCheck and waitForEndOfAdCheck
  * changed name of *testCompanionAd* to *testCompanionAdPresence*
  * removed *testCompanionAdVanish*
* Removed if-else statements from utility methods
* Changed *waitForCompanionAdCheck* and *waitForEndOfAdCheck* from booleans to voids
* Updated javadoc comments
* removed extraneous imports
I have not seen the @param syntax: "type name description..." before.  I've always seen "name description...".  It would be good for you to double check and make sure what you have is correct, in which case you will have taught me something.  I like the redundancy but I'm likely to be in the minority.