fix context for cascade-saving and saving existing object (#6735)

* added test cases

* fixed unparsed context when updating object

* fixed context inheritance for cascade-saved objects

* upgraded parse dependecy to 2.14.0

* rebuild

* removed superfluous comments

* undo lint changes

src/RestWrite.js

@@ -52,12 +52,13 @@ function RestWrite(
     this.runOptions.action = action;
   }
 
+  // Parse context
+  if (data._context && data._context instanceof Object) {
+    this.context = data._context;
+    delete data._context;
+  }
+
   if (!query) {
-    // Parse context
-    if (data._context && data._context instanceof Object) {
-      this.context = data._context;
-      delete data._context;
-    }
     if (this.config.allowCustomObjectId) {
       if (
         Object.prototype.hasOwnProperty.call(data, 'objectId') &&

src/batch.js

@@ -91,8 +91,8 @@ function handleBatch(router, req) {
   return initialPromise.then(() => {
     const promises = req.body.requests.map(restRequest => {
       const routablePath = makeRoutablePath(restRequest.path);
-      // Construct a request that we can send to a handler
 
+      // Construct a request that we can send to a handler
       const request = {
         body: restRequest.body,
         config: req.config,
@@ -100,6 +100,9 @@ function handleBatch(router, req) {
         info: req.info,
       };
 
+      // Add context to request body
+      if (req.body._context) { request.body._context = req.body._context; }
+
       return router
         .tryRouteRequest(restRequest.method, routablePath, request)
         .then(