Custom formatter cleanup Fix case where displaying a class constructor generated unreadable huge ou…

pkg/dev_compiler/test/codegen_expected/sunflower/sunflower.js

 define(['dart_sdk'], function(dart_sdk) {
   'use strict';
   const core = dart_sdk.core;
   const html = dart_sdk.html;
   const math = dart_sdk.math;
   const dart = dart_sdk.dart;
   const dartx = dart_sdk.dartx;
   const sunflower = Object.create(null);
   const circle = Object.create(null);
   const painter = Object.create(null);
@@ skipping 105 matching lines @@
   dart.defineLazy(painter, {
     get canvas() {
       return html.CanvasElement.as(painter.querySelector("#canvas"));
     }
   });
   dart.defineLazy(painter, {
     get context() {
       return html.CanvasRenderingContext2D.as(painter.canvas[dartx.getContext]('2d'));
     }
   });
+  dart.trackLibraries("sunflower", {"sunflower.dart": sunflower, "circle.dart": circle, "painter.dart": painter});
   // Exports:
   return {
     sunflower: sunflower,
     circle: circle,
     painter: painter
   };
 });
 
 //# sourceMappingURL=sunflower.js.map