title: addUIInterruptionMonitor(withDescription:handler:) not working on iOS 10 or 9
body: <p>The following tests works fine on iOS 11. It dismisses the alert asking permissions to use the locations services and then zooms in in the map. On iOS 10 or 9, it does none of this and the test still succeeds</p>
  
  <pre><code>func testExample() {
      let app = XCUIApplication()
  
      var handled = false
      var appeared = false
  
      let token = addUIInterruptionMonitor(withDescription: "Location") { (alert) -&gt; Bool in
          appeared = true
          let allow = alert.buttons["Allow"]
          if allow.exists {
              allow.tap()
              handled = true
              return true
          }
  
          return false
      }
  
      // Interruption won't happen without some kind of action.
      app.tap()
  
      removeUIInterruptionMonitor(token)
      XCTAssertTrue(appeared &amp;&amp; handled)
  }
  </code></pre>
  
  <p>Does anyone have an idea why and/or a workaround?</p>
  
  <p>Here's a project where you can reproduce the issue: <a href="https://github.com/TitouanVanBelle/Map" rel="noreferrer">https://github.com/TitouanVanBelle/Map</a></p>
  
  <p><em>Update</em></p>
  
  <p>Xcode 9.3 Beta's Changelogs show the following</p>
  
  <blockquote>
    <p>XCTest UI interruption monitors now work correctly on devices and simulators running iOS 10. (33278282)</p>
  </blockquote>