[TIMOB-27851] iOS: Ti.Network.createHTTPClient memory leak

Description

HTTPClient is leaking memory causing an eventual crash, appears to have only been introduced in 9.0.0.GA, could be regression on this issue: TIMOB-26811

How to reproduce

This sample will fire 20 url fetches every 1 second, it clearly shows the memory leak in xcode instruments. Do not run for long too long... Index.js

var triggerLoop = function() {
  _.times(20, fetchUrl);
};

function fetchUrl() {
      var client = Ti.Network.createHTTPClient({
        onload: function(e) {
            client = null;
        },
        onerror: function(e) {
          client = null;
        },
        timeout: 1000
      });
      client.open(
        "GET",
        "https://example.com/"
      );
      client.send();
      console.log("Fetching Url");
}

setInterval(triggerLoop,1000);

If you monitor with xcode leaks profiler, you will see a large amount of leaks from CFNetwork, I have attached the screenshots of profiling tool results.