Repository: react-native
Issue: zIndex in a List
Labels: Help Wanted :octocat:,Issue: Author Provided Repro,Component: FlatList,Bug

<!--
  We use GitHub Issues exclusively for tracking bugs in React Native.
  Questions? Visit http://facebook.github.io/react-native/help.html
  If this issue is about documentation or the website, please file it at:
  https://github.com/facebook/react-native-website/issues/new
-->

- [x] I have reviewed the [documentation](https://facebook.github.io/react-native)
- [x] I have searched [existing issues](https://github.com/facebook/react-native/issues)
- [x] I am using the [latest React Native version](https://github.com/facebook/react-native/releases)

<!-- Describe your issue in detail. -->
This is actually a reopen of my #16878 issue. I've got some thumbs up, so I think I am not the only one with this issue. This time I updated my example project to a pure rn project with the latest release ([rn Branche](https://github.com/TheNoim/zIndexBug/tree/rn))

## Environment
<!-- Required. Run `react-native info` in your terminal and paste its contents here. -->
```
info
  React Native Environment Info:
    System:
      OS: macOS High Sierra 10.13.6
      CPU: (8) x64 Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz
      Memory: 94.53 MB / 16.00 GB
      Shell: 5.3 - /bin/zsh
    Binaries:
      Node: 10.12.0 - ~/.nvm/versions/node/v10.12.0/bin/node
      Yarn: 1.16.0 - ~/.nvm/versions/node/v10.12.0/bin/yarn
      npm: 6.9.0 - /usr/local/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 12.1, macOS 10.14, tvOS 12.1, watchOS 5.1
      Android SDK:
        API Levels: 23
        Build Tools: 23.0.1
    IDEs:
      Xcode: 10.1/10B61 - /usr/bin/xcodebuild
    npmPackages:
      react: 16.8.3 => 16.8.3
      react-native: 0.59.8 => 0.59.8
    npmGlobalPackages:
      react-native-cli: 2.0.1
      react-native-git-upgrade: 0.2.7
```

## Steps to Reproduce
<!-- 
  Required. Let us know how to reproduce the issue. Include a code sample, share a project, 
  or share an app that reproduces the issue using [Snack](https://snack.expo.io/).
-->

1. Make a list (FlatList or Array.map, it happens with both)
2. The renderItem should get an onPress event
3. The onPress event changes the style to a high zIndex and position absolute
## Expected Behavior
I expect that the component with the high zIndex is over every other component.

## Actual Behavior
<!-- Write what happened. Include screenshots if needed. If this is a regression, let us know. -->
It seems like it ignores the zIndex property. The behavior is exactly like I would not apply any zIndex. I can remove the zIndex and I get the same result. 
[Google Drive Link](https://drive.google.com/file/d/1sqsjFTZwLdMe4zWzq8QV7ouV2xW84Lc2/view?usp=sharing) to a screenshot.

### Reproducible Demo

[Github Demo Project rn Branche](https://github.com/TheNoim/zIndexBug/tree/rn) This is just an extract out of my current rn project.
[Expo Link](https://expo.io/@noim/zindexbug) (Not on the latest rn version)
[Google Drive Video which show the issue](https://drive.google.com/file/d/15KRnOCOdWQhnQMA9IIforTDjcZH_k3jD/view?usp=sharing)