[TIMOB-12709] MobileWeb: HTTPClient send() throws CORS errors when posting some data, but works with no data

// works
var payload={"a":"1", "b":"2", "c":"testing"};
xhr.open('POST', 'http://' + env.hostname + ':9669?data=' + payload);
xhr.send();

// does not work
xhr.open('POST', 'http://localhost:9669');
xhr.send({"a":"1", "b":"2", "c":"testing"});