When debugging modifier_only_shortcut_test in _waylandonly mode I saw
that it was failing, among other things, because some aspects were not
initialised.
This changes every test we have to run the new
Test::initWaylandWorkspace() that calls waylandServer()->initWorkspace()
but also makes sure that WaylandServer::initialized is emitted before we
proceed.
Otherwise the input method test seems to fail with the following error
"The name org.kde.kwin.testvirtualkeyboard was not provided by any
.service files"
There were multiple other cases of placing the mouse between screens at
the start of tests. It seems to be all copy paste.
Only maximise and pointerConstraints were failing before this, but we
may as well fix all of them.
