Generate better code for '=='.

pkg/dev_compiler/test/codegen_expected/async_helper.js

 define(['dart_sdk'], function(dart_sdk) {
   'use strict';
   const core = dart_sdk.core;
   const dart = dart_sdk.dart;
   const dartx = dart_sdk.dartx;
   const async_helper = Object.create(null);
   let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.fnTypeFuzzy(dart.dynamic, [])))();
   let StringToException = () => (StringToException = dart.constFn(dart.fnType(core.Exception, [core.String])))();
   let _Action0Tovoid = () => (_Action0Tovoid = dart.constFn(dart.fnType(dart.void, [async_helper._Action0])))();
   let VoidTovoid = () => (VoidTovoid = dart.constFn(dart.fnType(dart.void, [])))();
@@ skipping 25 matching lines @@
     async_helper._initialized = false;
     async_helper._onAsyncEnd = callback;
   };
   dart.fn(async_helper.asyncTestInitialize, _Action0Tovoid());
   dart.copyProperties(async_helper, {
     get asyncTestStarted() {
       return async_helper._initialized;
     }
   });
   async_helper.asyncStart = function() {
-    if (dart.test(async_helper._initialized) && async_helper._asyncLevel == 0) {
+    if (dart.test(async_helper._initialized) && async_helper._asyncLevel === 0) {
       dart.throw(async_helper._buildException('asyncStart() was called even though we are done ' + 'with testing.'));
     }
     if (!dart.test(async_helper._initialized)) {
       if (async_helper._onAsyncEnd == null) {
         dart.throw(async_helper._buildException('asyncStart() was called before asyncTestInitialize()'));
       }
       core.print('unittest-suite-wait-for-done');
       async_helper._initialized = true;
     }
     async_helper._asyncLevel = dart.notNull(async_helper._asyncLevel) + 1;
   };
   dart.fn(async_helper.asyncStart, VoidTovoid());
   async_helper.asyncEnd = function() {
     if (dart.notNull(async_helper._asyncLevel) <= 0) {
       if (!dart.test(async_helper._initialized)) {
         dart.throw(async_helper._buildException('asyncEnd() was called before asyncStart().'));
       } else {
         dart.throw(async_helper._buildException('asyncEnd() was called more often than ' + 'asyncStart().'));
       }
     }
     async_helper._asyncLevel = dart.notNull(async_helper._asyncLevel) - 1;
-    if (async_helper._asyncLevel == 0) {
+    if (async_helper._asyncLevel === 0) {
       let callback = async_helper._onAsyncEnd;
       async_helper._onAsyncEnd = null;
       callback();
       core.print('unittest-suite-success');
     }
   };
   dart.fn(async_helper.asyncEnd, VoidTovoid());
   async_helper.asyncSuccess = function(_) {
     return async_helper.asyncEnd();
   };
   dart.fn(async_helper.asyncSuccess, dynamicTovoid());
   async_helper.asyncTest = function(f) {
     async_helper.asyncStart();
     dart.dsend(f(), 'then', async_helper.asyncSuccess);
   };
   dart.fn(async_helper.asyncTest, FnTovoid());
   dart.trackLibraries("async_helper", {
     "async_helper.dart": async_helper
   }, null);
   // Exports:
   return {
     async_helper: async_helper
   };
 });