QWebEnginePage::WebWindowType not covered by tests

We run web engine page test with tst_qwebenginepage ,however
function QWebEnginePage::createWindow has WebWindowType parameter
which is never tested.

Create test function which checks if WebWindowType is correct type

to trigger for example QWebEnginePage::WebDialog

following content has to be loaded:

https://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_win_opener

when button is clicked QWebEnginePage::createWindow should be called with WebWindowType == WebDialog