[TIMOB-17572] iOS: Fix activity indicator animation in list items

[hansemannn]

JIRA: https://jira.appcelerator.org/browse/TIMOB-17572

[build]

	Messages
📖	💾 Here's the generated SDK zipfile.

Generated by 🚫 dangerJS

[vijaysingh-axway]

CR passed.

[ssjsamir]

FR Passed: Activity indicator no longer freezes when updating list.

Test steps:

• Built a new SDK from https://jenkins.appcelerator.org/job/titanium-sdk/job/titanium_mobile/job/PR-9716/2/artifact/dist/mobilesdk-7.1.0.v20180114192248-osx.zip
• Created a new titanium project
• Added the test case mentioned in https://jira.appcelerator.org/browse/TIMOB-17572

var win = Ti.UI.createWindow({
  backgroundColor: 'white'
});

var listTemplate = {
  childTemplates: [{
    type: 'Ti.UI.Label',
    bindId: 'info',
    properties: {
      color: 'black',
      font: {
        fontFamily: 'Arial',
        fontSize: '20dp',
        fontWeight: 'bold'
      },
      left: '60dp',
      top: 0,
    }
  }]
};
var loadTemplate = {
  childTemplates: [{
    type: 'Ti.UI.ActivityIndicator',
    bindId: 'ai',
    properties: {
      left: 12,
      font: {
        fontSize: 16,
        fontFamily: 'Helvetica',
        fontWeight: 'bold',
      },
      color: "black",
      style: Ti.UI.ActivityIndicatorStyle.DARK,
      height: 55,
      visible: true
    }
  }]
}; 
var list = Ti.UI.createListView({
  templates: {
    'item': listTemplate,
    'load': loadTemplate
  },
});
var sections = []; 
var fruitSection = Ti.UI.createListSection({
  headerTitle: 'Fruits / Frutas'
});
var fruitDataSet = [{
    template: 'item',
    info: {
      text: 'Apple'
    }
  },
  {
    template: 'item',
    info: {
      text: 'Banana'
    }
  }
];
fruitSection.setItems(fruitDataSet);
sections.push(fruitSection); 
list.setSections(sections); 
var iterations = 1; 
var createListDataItems = function() {
  var items = fruitDataSet;
  fruitDataSet.pop();
  for (var i = 1; i <= 2; i++) {
    items.push({
      template: 'item',
      info: {
        text: 'added ' + iterations + i
      }
    });
  }
  iterations++; 
  return items;
}; 
var createLoadingTransactionsListItem = function() {
  var items = fruitDataSet;
  items.push({
    template: 'load',
    ai: {
      message: ' Loading...'
    }
  }); 
  return items;
}; 
var loadMore = function() {
  // show loading message
  fruitSection.setItems(createLoadingTransactionsListItem()); 
  setTimeout(function() {
    // append more items
    fruitSection.setItems(createListDataItems()); 
    list.setMarker({
      sectionIndex: 0,
      itemIndex: fruitSection.items.length - 2
    }); 
  }, 2000);
};
list.addEventListener('marker', loadMore); 
setTimeout(loadMore, 0); 
win.add(list);
win.open();

• Ran the program
• Saw the Activity indicator spinning
• Refreshed the list to add more items
• Saw that the activity indicator was still spinning

Test Environment
Appcelerator Command-Line Interface, version 7.0.1
iphone 6+ (10.2)
Operating System Name: Mac OS High Sierra
Operating System Version: 10.13
Node.js Version: 8.9.1
Xcode: 9.2
Appcelerator Studio: 5.0.0.201712081732