title: Json file as parameter in Jenkins pipeline
body: <p>I am facing an issue where I want my testing suites to be controlled during runtime based on a parameter selected.
  My jenkins file has parameters as below.  </p>
  
  <pre><code>choice(choices: 'google.com\flights.google.com\nbooks.google.com',name: 'TestSite',description: 'Which site you want to build and test?')
  </code></pre>
  
  <p>Now based on selection of TestSite, I want my Json file to be populated on second parameter which has test suites names.  </p>
  
  <pre><code>"google": {
      "all": "./spec/**/**.spec.js"
    },
    "books": {
      "all": "./spec/**/**.spec.js",
      "account": "./spec/account/**.spec.js"
    }
  </code></pre>
  
  <p>Can someone please suggest if they are able to achieve this in Jenkins pipeline? Basically populating a parameter during run time after selection of another parameter?</p>