[autotests] Try making QuickTilingTest::testShortcut more robust

It failed on CI. A possibility is that the wait for the quick tile
changed took to long, so that the next wait already passed and thus
failed. Instead of wait a QTRY_COMPARE on the size of the signalspy.

autotests/integration/quick_tiling_test.cpp

@@ -678,8 +678,7 @@ void QuickTilingTest::testShortcut()
     QCOMPARE(c->quickTileMode(), expectedMode);
 
     // but we got requested a new geometry
-    QVERIFY(sizeChangeSpy.wait());
-    QCOMPARE(sizeChangeSpy.count(), 1);
+    QTRY_COMPARE(sizeChangeSpy.count(), 1);
     QCOMPARE(sizeChangeSpy.first().first().toSize(), expectedGeometry.size());
 
     // attach a new image