make class final

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/expression/TernaryIfNode.java

@@ -42,7 +42,7 @@
 
 import com.oracle.truffle.api.frame.VirtualFrame;
 
-public class TernaryIfNode extends ExpressionNode {
+public final class TernaryIfNode extends ExpressionNode {
     @Child private CastToBooleanNode condition;
     @Child private ExpressionNode then;
     @Child private ExpressionNode orelse;