Fix invalid cast in test

Author: Oren Novotny

crypto/test/src/crmf/test/CrmfTest.cs

@@ -156,7 +156,7 @@ private void CheckCertReqMsgWithArchiveControl(AsymmetricCipherKeyPair kp, Certi
             IsTrue(archiveControl.EnvelopedData);
             RecipientInformationStore recips = archiveControl.GetEnvelopedData().GetRecipientInfos();
 
-            ArrayList collection =  (ArrayList)recips.GetRecipients();
+            IList collection =  (IList)recips.GetRecipients();
 
             IsTrue(collection.Count == 1);
             KeyTransRecipientInformation info = (KeyTransRecipientInformation)collection[0];