Fix sitelinklistview tests and some edge cases

Fixed edge cases:

* enterNewItem() does not create two empty sitelinkviews if the sitelinklistview
  is not yet in edit mode
* _removeSitelinkviewIfEmpty gets the event passed instead of relying on the
  global event property
* isValid can actually return false

Also added two tests.

Change-Id: Ib093592c84e350d129350316afec7c6e6b508f95
Merge "Fix sitelinklistview tests and some edge cases"