Fix crash when using type parameters on custom elements

pkg/compiler/lib/src/ssa/locals_handler.dart

 // Copyright (c) 2016, 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.
 
 import '../closure.dart';
 import '../common.dart';
 import '../compiler.dart' show Compiler;
 import '../elements/resolution_types.dart';
 import '../elements/elements.dart';
 import '../io/source_information.dart';
@@ skipping 258 matching lines @@
       }
     } else if (isNativeUpgradeFactory) {
       SyntheticLocal parameter =
           new SyntheticLocal('receiver', executableContext);
       // Unlike `this`, receiver is nullable since direct calls to generative
       // constructor call the constructor with `null`.
       HParameterValue value =
           new HParameterValue(parameter, new TypeMask.exact(cls, closedWorld));
       builder.graph.explicitReceiverParameter = value;
       builder.graph.entry.addAtEntry(value);
+      if (builder.lastAddedParameter == null) {
+        // If this is the first parameter inserted, make sure it stays first.
+        builder.lastAddedParameter = value;
+      }
     }
   }
 
   /// Returns true if the local can be accessed directly. Boxed variables or
   /// captured variables that are stored in the closure-field return [:false:].
   bool isAccessedDirectly(Local local) {
     assert(local != null);
     return !redirectionMapping.containsKey(local) &&
         !closureData.variablesUsedInTryOrGenerator.contains(local);
   }
@@ skipping 373 matching lines @@
   final ExecutableElement executableContext;
 
   // Avoid slow Object.hashCode.
   final int hashCode = _nextHashCode = (_nextHashCode + 1).toUnsigned(30);
   static int _nextHashCode = 0;
 
   SyntheticLocal(this.name, this.executableContext);
 
   toString() => 'SyntheticLocal($name)';
 }