Do not suppress implicit constructors that need a super call.

lib/runtime/dart/_js_helper.js

 var _js_helper;
 (function(exports) {
   'use strict';
   class NoSideEffects extends core.Object {
     NoSideEffects() {
     }
   }
   class NoThrows extends core.Object {
     NoThrows() {
     }
@@ skipping 2865 matching lines @@
   Closure.NAME_INDEX = 1;
   Closure.CALL_NAME_INDEX = 2;
   Closure.REQUIRED_PARAMETER_INDEX = 3;
   Closure.OPTIONAL_PARAMETER_INDEX = 4;
   Closure.DEFAULT_ARGUMENTS_INDEX = 5;
   Closure.functionCounter = 0;
   // Function closureFromTearOff: (dynamic, dynamic, dynamic, dynamic, dynamic, dynamic) → dynamic
   function closureFromTearOff(receiver, functions, reflectionInfo, isStatic, jsArguments, name) {
     return Closure.fromTearOff(receiver, _interceptors.JSArray.markFixedList(dart.as(functions, core.List)), _interceptors.JSArray.markFixedList(dart.as(reflectionInfo, core.List)), !!isStatic, jsArguments, name);
   }
-  class TearOffClosure extends Closure {}
+  class TearOffClosure extends Closure {
+    TearOffClosure() {
+      super.Closure();
+    }
+  }
   let _self = Symbol('_self');
   let _target = Symbol('_target');
   let _name = Symbol('_name');
   class BoundClosure extends TearOffClosure {
     BoundClosure(self, target, receiver, name) {
       this[_self] = self;
       this[_target] = target;
       this[_receiver] = receiver;
       this[_name] = name;
     }
@@ skipping 1176 matching lines @@
   exports.jsonEncodeNative = jsonEncodeNative;
   exports.getIsolateAffinityTag = getIsolateAffinityTag;
   exports.LoadLibraryFunctionType = LoadLibraryFunctionType;
   exports.DeferredLoadCallback = DeferredLoadCallback;
   exports.loadDeferredLibrary = loadDeferredLibrary;
   exports.MainError = MainError;
   exports.missingMain = missingMain;
   exports.badMain = badMain;
   exports.mainHasTooManyParameters = mainHasTooManyParameters;
 })(_js_helper || (_js_helper = {}));