Stabilize test_urlProperty

Pulls in Chromium patches that fixes crashes in the test, and add
a missing waitForLoadSucceeded, that otherwise might cause the
next test to fail.

Task-number: QTBUG-48031
Change-Id: I4844aee0ccf159e50de955f3b3da704160a4a0f5
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>