SquishTests: Don't call waitForCleanShutdown() at end of translation test

It gets called by the following __removeTestingDir__().

Change-Id: I8846f8b841063053d56f7cbe7c1d3cd37655aa73
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

tests/system/suite_general/tst_installed_languages/test.py

@@ -32,6 +32,5 @@ def main():
         except:
             test.fail("Creator seems to be missing %s translation" % languageName)
             sendEvent("QCloseEvent", ":Qt Creator_Core::Internal::MainWindow")
-        waitForCleanShutdown()
         __removeTestingDir__()
         copySettingsToTmpDir()