Bug 417142 - [Viewers] Update Viewer JUnit tests to use generics

-Added Testcase for the generic ArrayContentProvider
-Updated Testcases to support the <? super I> changes for the
ContentProvider

Also includes changes from change
Ic9b25517d81e78ed3c15576b4956b791278ca682

Change-Id: Ic5f774516c032c99e8f890cc82c61cbd76dc6d78
Signed-off-by: Hendrik Still <hendrik.still@gammas.de>