SquishTests: Avoid crash in test

Workaround crash inside a test that may happen if the
test tries to wait for an object when the AUT is gone already.
Check for a clean exit and only if this is not the case
try to continue with the error handling.

Change-Id: I65f3e72cd343ec527ad822de915bc0c49c263153
Reviewed-by: Robert Löhning <robert.loehning@qt.io>

tests/system/suite_editors/tst_modify_readonly/test.py

@@ -85,6 +85,13 @@ def testSaveChangesAndMakeWritable(modifiedFiles, readOnlyFiles):
     except:
         test.fatal("Missing dialog regarding missing permission on read only files.")
     exitCanceled = False
+
+    # workaround crashing test
+    # (AUT stopped responding / AUT '' did not respond to network communication)
+    __shutdownDone__ = lambda : not currentApplicationContext().isRunning
+    if test.verify(waitFor(__shutdownDone__, 1000), "Clean exit of Qt Creator."):
+        return
+
     try:
         mBoxStr = "{type='QMessageBox' unnamed='1' visible='1' text?='*Could not save the files.'}"
         msgBox = waitForObject(mBoxStr, 3000)