Fix a batch of DDC SDK compile errors.

sdk/lib/core/int.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.core;
 
 /**
  * An arbitrarily large integer.
  *
  * **Note:** When compiling to JavaScript, integers are
@@ skipping 12 matching lines @@
    *
    * The result is the same as would be returned by:
    *
    *     int.parse(const String.fromEnvironment(name, defaultValue: ""),
    *               (_) => defaultValue)
    *
    * Example:
    *
    *     const int.fromEnvironment("defaultPort", defaultValue: 80)
    */
+  // The .fromEnvironment() constructors are special in that we do not want
+  // users to call them using "new". We prohibit that by giving them bodies
+  // that throw, even though const constructors are not allowed to have bodies.
+  // Disable those static errors.
+  //ignore: const_constructor_with_body
+  //ignore: const_factory
   external const factory int.fromEnvironment(String name, {int defaultValue});
 
   /**
    * Bit-wise and operator.
    *
    * Treating both `this` and [other] as sufficiently large two's component
    * integers, the result is a number with only the bits set that are set in
    * both `this` and [other]
    *
    * Of both operands are negative, the result is negative, otherwise
@@ skipping 267 matching lines @@
    *
    *     var value = int.parse(text, onError: (source) => null);
    *     if (value == null) ... handle the problem
    *
    * The [onError] function is only invoked if [source] is a [String]. It is
    * not invoked if the [source] is, for example, `null`.
    */
   external static int parse(String source,
       {int radix, int onError(String source)});
 }