Fix a batch of DDC SDK compile errors.

sdk/lib/core/int.dart

Index: sdk/lib/core/int.dart
diff --git a/sdk/lib/core/int.dart b/sdk/lib/core/int.dart
index 217960d07fdc3c37f9d0afef34890157fc82a2cb..c28679e0136399be508a77f2651790be5dfdd45a 100644
--- a/sdk/lib/core/int.dart
+++ b/sdk/lib/core/int.dart
@@ -30,6 +30,12 @@ abstract class int extends num {
    *
    *     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});
 
   /**