Disable version checking during system tests

re #12064

Code/Mantid/Testing/SystemTests/lib/systemtests/stresstesting.py

@@ -999,6 +999,9 @@ class MantidFrameworkConfig:
 
         # Do not update instrument definitions
         config['UpdateInstrumentDefinitions.OnStartup'] = "0"
+        
+        # Do not perform a version check
+        config['CheckMantidVersion.OnStartup'] = "0"
 
         # Disable usage reports
         config['usagereports.enabled'] = "0"