[sailfish-browser] Fix failing tst_webview

Reverts title change handling from DeclarativeWebContainer::onActiveTabChanged that was introduced in commit ad85e79d.

Adds title changed and urlchanged helpers so that we do not emit signals unnecessarily. 

CloseActiveTab does not trigger load anymore (SHA1 ad85e79dda). So, activatePage in test case.
None! I had it a bit differently previously, so left over. Thanks for catching! Same seems to apply for title.