typo addd in tests

Author: affeldt-aist

tests/missing_join_error.v.out

@@ -1,5 +1,5 @@
 The command has indeed failed with message:
-You must declare the hierarchy bottom-up or addd a missing join. 
+You must declare the hierarchy bottom-up or add a missing join. 
 There are two ways out: 
 - declare structure A2B1 before structure B2A1 if B2A1 inherits from it; 
 - declare an additional structure that inherits from both A1 and A2 and from which A2B1 and/or B2A1 inherit.