small cleanups

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/set/FrozenSetBuiltins.java

@@ -156,7 +156,7 @@ abstract static class AndNode extends PythonBinaryBuiltinNode {
         private HashingStorageNodes.SetItemNode getSetItemNode() {
             if (setItemNode == null) {
                 CompilerDirectives.transferToInterpreterAndInvalidate();
-                setItemNode = HashingStorageNodes.SetItemNode.create();
+                setItemNode = insert(HashingStorageNodes.SetItemNode.create());
             }
             return setItemNode;
         }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/PBaseNode.java

@@ -55,7 +55,6 @@
 import com.oracle.truffle.api.nodes.Node;
 
 public abstract class PBaseNode extends Node {
-    @CompilationFinal private PythonContext context;
     @Child private PythonObjectFactory factory;
     @CompilationFinal private ContextReference<PythonContext> contextRef;