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UICollectionView.reloadItems(at:) is broken. Causes strange reloading of the same cell multiple times for different index paths.

iPhone Pro Max Simulator
Xcode 11.3
macOS 10.14.4

Steps to repro:
1. Run the attached project on iPhone 11 Pro Max Simulator.
2. We call `self.collectionView.reloadItems(at: [IndexPath(item: 2, section: 0)])`

Expected: Only a single index path is reloaded.

Actual: 4 index paths are reloaded.
```
<CollectionViewMayhem.FooCell: 0x7fe7f5606e10; baseClass = UICollectionViewCell; frame = (60.6667 0; 50 50); layer = <CALayer: 0x600001b488e0>>, [0, 1]
<CollectionViewMayhem.FooCell: 0x7fe7f5606e10; baseClass = UICollectionViewCell; frame = (0 0; 50 50); hidden = YES; layer = <CALayer: 0x600001b488e0>>, [0, 0]
<CollectionViewMayhem.FooCell: 0x7fe7f5606e10; baseClass = UICollectionViewCell; frame = (121.333 0; 50 50); hidden = YES; layer = <CALayer: 0x600001b488e0>>, [0, 2]
<CollectionViewMayhem.FooCell: 0x7fe7f5606e10; baseClass = UICollectionViewCell; frame = (121.333 0; 50 50); hidden = YES; layer = <CALayer: 0x600001b488e0>>, [0, 2]
```

The workaround is to just use `reloadData()` but that's not ideal.

Please let me know if you have any questions. Thanks!

Here's the sample code:

++++++++++

import UIKit

class FooCell: UICollectionViewCell {}

class ViewController: UIViewController, UICollectionViewDataSource {

    @IBOutlet var collectionView: UICollectionView!

    override func viewDidLoad() {
        super.viewDidLoad()
        collectionView.register(FooCell.self, forCellWithReuseIdentifier: "Foo")
        DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
            print("Reloading")
            self.collectionView.reloadItems(at: [IndexPath(item: 2, section: 0)])
        }
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 3
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Foo", for: indexPath)
        print("\(cell), \(indexPath)")
        return cell
    }
}