Fix tooltip test problems caused by #12458

Tooltips are no longer removed but moved outside the viewport,
which broke several tests.

Rewrite related tests using TB4 to be stable across all
browsers. There are differences between browsers (e.g.
position -999 or -1000, gwt-uid-* varied between browsers
etc.) so TB2 tests kept failing on some or all browsers.

Some tests have been renamed to better indicate what they
do.

Change-Id: Ia7276871f3c26d506dc70e1719347d020b547bfc