Fix exception type

Author: peterdettman

core/src/main/java/org/bouncycastle/crypto/digests/AsconXofBase.java

@@ -100,7 +100,7 @@ private void ensureNoAbsorbWhileSqueezing(boolean m_squeezing)
     {
         if (m_squeezing)
         {
-            throw new IllegalArgumentException("attempt to absorb while squeezing");
+            throw new IllegalStateException("attempt to absorb while squeezing");
         }
     }
 }