Remove support for 'argument definitions test' from dart2js.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.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 js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 991 matching lines @@
         argumentsBuffer[count] = js(jsName);
       } else {
         int index = names.indexOf(element.name);
         if (index != -1) {
           indexOfLastOptionalArgumentInParameters = count;
           // The order of the named arguments is not the same as the
           // one in the real method (which is in Dart source order).
           argumentsBuffer[count] = js(jsName);
           parametersBuffer[optionalParameterStart + index] =
               new jsAst.Parameter(jsName);
-        // Note that [elements] may be null for a synthesized [member].
-        } else if (elements != null && elements.isParameterChecked(element)) {
-          argumentsBuffer[count] = constantReference(SentinelConstant.SENTINEL);
         } else {
           Constant value = handler.initialVariableValues[element];
           if (value == null) {
             argumentsBuffer[count] = constantReference(new NullConstant());
           } else {
             if (!value.isNull()) {
               // If the value is the null constant, we should not pass it
               // down to the native method.
               indexOfLastOptionalArgumentInParameters = count;
             }
@@ skipping 2617 matching lines @@
 
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;