Fix: initialize node.

Author: fangerer

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

@@ -70,6 +70,7 @@
 import com.oracle.graal.python.builtins.objects.bytes.PBytes;
 import com.oracle.graal.python.builtins.objects.bytes.PIBytesLike;
 import com.oracle.graal.python.builtins.objects.common.SequenceNodes.LenNode;
+import com.oracle.graal.python.builtins.objects.common.SequenceNodes;
 import com.oracle.graal.python.builtins.objects.common.SequenceStorageNodes;
 import com.oracle.graal.python.builtins.objects.common.SequenceStorageNodes.GetItemNode;
 import com.oracle.graal.python.builtins.objects.common.SequenceStorageNodes.ToByteArrayNode;
@@ -932,7 +933,7 @@ Object utimeError(Object path, Object times, Object ns, Object dir_fd, Object fo
         }
 
         private long getTime(PTuple times, int index, String argname) {
-            if (lenNode.execute(times) <= index) {
+            if (getLength(times) <= index) {
                 throw tupleError(argname);
             }
             if (getItemNode == null) {
@@ -979,6 +980,14 @@ private void setAtime(String path, long mtime) {
             } catch (IOException e) {
             }
         }
+
+        private int getLength(PTuple times) {
+            if (lenNode == null) {
+                CompilerDirectives.transferToInterpreterAndInvalidate();
+                lenNode = insert(SequenceNodes.LenNode.create());
+            }
+            return lenNode.execute(times);
+        }
     }
 
     // FIXME: this is not nearly ready, just good enough for now