started refactoring tests

testExecuteIndex_default() does not depend now on wfMessage() now; the test used to check data prepared for the template (and there wfMessage() is being used), now the test checks if various methods are called when they are supposed to be called
refactored testExecuteIndex_with_edit()

The test does not depend now on wfMessage(); It used to check data prepared for the template (and there wfMessage() is being used), now it checks if various methods are called when they are supposed to be called.

Added new helper method getContributeMenuControllerMock()
refactored testExecuteIndex_with_edit_nav()

The test does not depend now on wfMessage(); It used to check data prepared for the template (and there wfMessage() is being used), now it checks if various methods are called when they are supposed to be called.
added new simple getter in ContributeMenuController

Removed old tests which depended on wfMessage() and added new simple one which tests ContributeMenuController::getSpecialPagesLinks()