Remove support for 'argument definitions test' from dart2js.

sdk/lib/_internal/compiler/implementation/dart_backend/placeholder_collector.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart_backend;
 
 class LocalPlaceholder {
   final String identifier;
   final Set<Node> nodes;
   LocalPlaceholder(this.identifier) : nodes = new Set<Node>();
@@ skipping 31 matching lines @@
 }
 
 class SendVisitor extends ResolvedVisitor {
   final PlaceholderCollector collector;
 
   get compiler => collector.compiler;
 
   SendVisitor(this.collector, TreeElements elements) : super(elements);
 
   visitOperatorSend(Send node) {
-    if (node.isParameterCheck) {
-      final element = elements[node.receiver];
-      if (element != null) {
-        collector.tryMakeLocalPlaceholder(element, node.receiver);
-      }
-    }
   }
 
   visitForeignSend(Send node) {}
 
   visitSuperSend(Send node) {
     Element element = elements[node];
     if (element != null && element.isConstructor()) {
       collector.makeRedirectingConstructorPlaceholder(node.selector, element);
     } else {
       collector.tryMakeMemberPlaceholder(node.selector);
@@ skipping 553 matching lines @@
 
   visitBlock(Block node) {
     for (Node statement in node.statements.nodes) {
       if (statement is VariableDefinitions) {
         makeVarDeclarationTypePlaceholder(statement);
       }
     }
     node.visitChildren(this);
   }
 }