fixes #43, remove => workaround

test/codegen/expect/BenchmarkBase.js

 var BenchmarkBase = dart.defineLibrary(BenchmarkBase, {});
 var core = dart.import(core);
 (function(exports, core) {
   'use strict';
   class Expect extends core.Object {
     static equals(expected, actual) {
       if (!dart.equals(expected, actual)) {
         throw `Values not equal: ${expected} vs ${actual}`;
       }
     }
@@ skipping 40 matching lines @@
       let elapsed = 0;
       while (dart.notNull(elapsed) < dart.notNull(timeMinimum)) {
         dart.dcall(f);
         elapsed = watch.elapsedMilliseconds;
         iter = dart.notNull(iter) + 1;
       }
       return 1000.0 * dart.notNull(elapsed) / dart.notNull(iter);
     }
     measure() {
       this.setup();
-      BenchmarkBase.measureFor(dart.fn((() => {
+      BenchmarkBase.measureFor(dart.fn(() => {
         this.warmup();
-      }).bind(this)), 100);
-      let result = BenchmarkBase.measureFor(dart.fn((() => {
+      }), 100);
+      let result = BenchmarkBase.measureFor(dart.fn(() => {
         this.exercise();
-      }).bind(this)), 2000);
+      }), 2000);
       this.teardown();
       return result;
     }
     report() {
       let score = this.measure();
       core.print(`${this.name}(RunTime): ${score} us.`);
     }
   }
   dart.setSignature(BenchmarkBase, {
     constructors: () => ({BenchmarkBase: [BenchmarkBase, [core.String]]}),
     methods: () => ({
       run: [dart.void, []],
       warmup: [dart.void, []],
       exercise: [dart.void, []],
       setup: [dart.void, []],
       teardown: [dart.void, []],
       measure: [core.double, []],
       report: [dart.void, []]
     }),
     statics: () => ({measureFor: [core.double, [core.Function, core.int]]}),
     names: ['measureFor']
   });
   // Exports:
   exports.Expect = Expect;
   exports.BenchmarkBase = BenchmarkBase;
 })(BenchmarkBase, core);