8233845: (sctp) Relax assertion in sun.nio.ch.sctp.AssociationChange::association

Reviewed-by: alanb

Author: ChrisHegarty

src/jdk.sctp/unix/classes/sun/nio/ch/sctp/AssociationChange.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -93,7 +93,7 @@ public void setAssociation(Association association) {
 
     @Override
     public Association association() {
-        assert association != null;
+        assert event == AssocChangeEvent.CANT_START ? true : association != null;
         return association;
     }