FunctionNode#getClosure: use System.arraycopy

Author: steve-s

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/BuiltinConstructors.java

@@ -136,9 +136,9 @@
 import com.oracle.graal.python.builtins.objects.common.HashingStorageLibrary;
 import com.oracle.graal.python.builtins.objects.common.SequenceNodes;
 import com.oracle.graal.python.builtins.objects.common.SequenceNodes.GetObjectArrayNode;
+import com.oracle.graal.python.builtins.objects.common.SequenceNodesFactory.GetObjectArrayNodeGen;
 import com.oracle.graal.python.builtins.objects.common.SequenceStorageNodes;
 import com.oracle.graal.python.builtins.objects.common.SequenceStorageNodes.NoGeneralizationNode;
-import com.oracle.graal.python.builtins.objects.common.SequenceNodesFactory.GetObjectArrayNodeGen;
 import com.oracle.graal.python.builtins.objects.complex.PComplex;
 import com.oracle.graal.python.builtins.objects.dict.PDict;
 import com.oracle.graal.python.builtins.objects.ellipsis.PEllipsis;
@@ -2186,12 +2186,8 @@ public PFunction function(Object cls, PCode code, PDict globals, String name, PT
         }
 
         private static PCell[] getClosure(Object[] closure) {
-            assert closure != null;
             PCell[] cells = new PCell[closure.length];
-            for (int i = 0; i < closure.length; i++) {
-                assert closure[i] instanceof PCell;
-                cells[i] = (PCell) closure[i];
-            }
+            PythonUtils.arraycopy(closure, 0, cells, 0, closure.length);
             return cells;
         }