title: nextToken in "queryAll" Query type
body: <p>I have a very simple Schema Structure in my AWS AppSync using DynamoDB as backend.</p>
  
  <pre><code>    type Demo {
          id: ID!
          name: String!
          date: String!
      }
  
      type DemoConnection {
          items: [Demo]
          nextToken: String
      }
  input ListFilter {
      limit: Int
      nextToken: String
  }
  </code></pre>
  
  <p>And i have this query to list all Demos</p>
  
  <pre><code>listAllDemo(input: ListFilter): DemoConnection
  </code></pre>
  
  <p>For which the resolvers looks as - </p>
  
  <pre><code>{
      "version" : "2017-02-28",
      "operation" : "Scan",
      "limit": #if($context.arguments.limit) $context.arguments.limit #else 10 #end,
      "nextToken": #if($context.arguments.input.nextToken) "$context.arguments.input.nextToken" #else null #end
  }
  </code></pre>
  
  <p>And Response Mapping Template as</p>
  
  <pre><code>{
      "items": $util.toJson($context.result.items),
      "nextToken": $util.toJson($context.result.nextToken)
  }
  </code></pre>
  
  <p>I created some 13 records to test the "nextToken". It returned a token along with 10 results and i used it to fetch the other results.
  There is some other API which deletes these records from DB. WHat happens is even when i am now having 7 records in DB, "<code>listAll</code>" returns the nextToken , which it should not, though using this nextToken the next resultset is blank.</p>
  
  <p>I am unable to understand why i am getting this nextToken even when records are not there.</p>