emit interfaces before use

lib/runtime/dart/_js_helper.js

Index: lib/runtime/dart/_js_helper.js
diff --git a/lib/runtime/dart/_js_helper.js b/lib/runtime/dart/_js_helper.js
index 52c29ccb4c7662d790f578befe427e339c797719..3eaadbca3385be43b99704efc705bcdcadb734af 100644
--- a/lib/runtime/dart/_js_helper.js
+++ b/lib/runtime/dart/_js_helper.js
@@ -1339,8 +1339,7 @@ var _js_helper;
     }
   }
   let patch = new _Patch();
-  class InternalMap extends core.Object {
-  }
+  class InternalMap extends core.Object {}
   // Function requiresPreamble: () → dynamic
   function requiresPreamble() {
   }
@@ -2822,8 +2821,7 @@ var _js_helper;
   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 {}
   let _self = Symbol('_self');
   let _target = Symbol('_target');
   let _name = Symbol('_name');
@@ -3182,8 +3180,7 @@ var _js_helper;
   }
   dart.defineLazyClass(exports, {
     get JavaScriptIndexingBehavior() {
-      class JavaScriptIndexingBehavior extends _interceptors.JSMutableIndexable {
-      }
+      class JavaScriptIndexingBehavior extends _interceptors.JSMutableIndexable {}
       return JavaScriptIndexingBehavior;
     }
   });