[ReactNative] Remove RCTJSTimers

Summary:
@public

Remove `RCTJSTimers.js`, the file was just an alias to `JSTimersExecution`.

Test Plan: Still builds.

Libraries/BatchedBridge/BatchedBridgedModules/RCTJSTimers.js

@@ -1,18 +0,0 @@
-/**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
- *
- * @providesModule RCTJSTimers
- * @flow
- */
-'use strict';
-
-var JSTimersExecution = require('JSTimersExecution');
-
-var RCTJSTimers = JSTimersExecution;
-
-module.exports = RCTJSTimers;

Libraries/ReactNative/ReactNativeDefaultInjection.js

@@ -40,7 +40,7 @@ var invariant = require('invariant');
 // Just to ensure this gets packaged, since its only caller is from Native.
 require('RCTEventEmitter');
 require('RCTLog');
-require('RCTJSTimers');
+require('JSTimersExecution');
 
 function inject() {
   /**