dart2js: Change how super tear-offs are registered.

pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart

Index: pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
diff --git a/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart b/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
index 4693bad24e8ef90ed0bb1a6ec76b2455c426fbc1..cd688d51ca51e9b5a202130e1f84f9b2f135dc94 100644
--- a/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
+++ b/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
@@ -236,6 +236,8 @@ class InvokeMethodDirectly extends Expression implements Invoke {
   InvokeMethodDirectly(this.receiver, this.target, this.selector,
       this.arguments, this.sourceInformation);
 
+  bool get isTearOff => selector.isGetter && !target.isGetter;
+
   accept(ExpressionVisitor visitor) => visitor.visitInvokeMethodDirectly(this);
   accept1(ExpressionVisitor1 visitor, arg) {
     return visitor.visitInvokeMethodDirectly(this, arg);