Blind fix for flaky print preview test

I faced the same problem in
https://cgit.freedesktop.org/libreoffice/contrib/dev-tools/commit/?id=f631db9e5e83706ed2678fb4db737700dd623a1b

Change-Id: I1adcc418e0efa7e77e1dda5b9dccd7c55cb5267f
Reviewed-on: https://gerrit.libreoffice.org/71280
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/qa/uitest/writer_tests5/tdf117039.py

@@ -24,6 +24,9 @@ class tdf117039(UITestCase):
         document = self.ui_test.get_component()
         self.xUITest.executeCommand(".uno:PrintPreview")  #open print preview
         self.xUITest.executeCommand(".uno:ClosePreview")  # close print preview
+
+        self.xUITest.getTopFocusWindow() #Get focus after closing preview
+
         #verify
         self.assertEqual(document.Text.String[0:22], "Test digital signature")
         self.ui_test.close_doc()

sw/qa/uitest/writer_tests5/tdf118540.py

@@ -29,6 +29,9 @@ class tdf118540(UITestCase):
         xOkBtn = xDialog.getChild("ok")
         xOkBtn.executeAction("CLICK", tuple())
         self.xUITest.executeCommand(".uno:ClosePreview")  # close print preview
+
+        self.xUITest.getTopFocusWindow() #Get focus after closing preview
+
         #verify
         self.assertEqual(document.Text.String[0:4], "Test")
         self.ui_test.close_doc()

sw/qa/uitest/writer_tests5/tdf121591.py

@@ -28,6 +28,9 @@ class tdf121591(UITestCase):
         #open and close print preview
         self.xUITest.executeCommand(".uno:PrintPreview")  #open print preview
         self.xUITest.executeCommand(".uno:ClosePreview")  # close print preview
+
+        self.xUITest.getTopFocusWindow() #Get focus after closing preview
+
         #verify nr. of frames
         self.assertEqual(document.TextFrames.getCount(), 1)