title: ios 11 UITabBar UITabBarItem positioning issue
body: <p>I have built my app using new Xcode 9 beta for ios 11. I have found an issue with UITabBar where items are spread through the UITabBar and title is right aligned to the image. I have tried changing the code to get it to work but still not successful. </p>
  
  <p>ios 10+ </p>
  
  <p><a href="https://i.stack.imgur.com/up2iM.png" rel="noreferrer"><img src="https://i.stack.imgur.com/up2iM.png" alt="enter image description here"></a></p>
  
  <p>ios 11</p>
  
  <p><a href="https://i.stack.imgur.com/4Lxt6.png" rel="noreferrer"><img src="https://i.stack.imgur.com/4Lxt6.png" alt="enter image description here"></a></p>
  
  <p>I could change the position of title using <code>tabBarItem.titlePositionAdjustment</code>
  But that is not my requirement as it should automatically come bellow the image itself. I tried setting <code>tabbar.itemPositioning to UITabBarItemPositioningCentered</code> and also tried changing <code>itemSpacing</code> and <code>width</code>, but still did not work. Can someone help me understand why this happens and how to fix this? I want it to like ios 10+ version and images are taken from the left most corner of an iPad.</p>