Adjust test result handling

Signed-off-by: Brendan Moran <brendan.moran@arm.com>

Author: bremoran

scripts/tests

@@ -759,6 +759,9 @@ class Tests:
 
         if resultss is None:
             self.check_fail()
+            return
+
+        self.check_fail()
 
         # NOTE: There will only be one items in resultss, as we haven't yet decided how to write both opt/no-opt benchmark results
         for k, results in resultss.items():