Repository: flutter
Issue: PlatformView shown on top after Navigator.push
Labels: platform-android,engine,a: platform-views,has reproducible steps,P2,found in release: 2.0,found in release: 2.3,team-android,triaged-android

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## Steps to Reproduce

<!-- You must include full steps to reproduce so that we can reproduce the problem. -->
1. Sample Repository https://github.com/ajaxspace/platfrom_view_sample_issue
2. Run app
3. Use remote to open second screen(tap select, or left/select on remote)
4. Observe screen
<!-- describe how to reproduce the problem -->

**Expected results:** <!-- what did you want to see? -->
Second screen is shown over platformView
**Actual results:** <!-- what did you see? -->
Second screen is shown below platformView

**Notes**:
Works correct on tablet.
Reproduced on Xiaomi Mi Stick

Demo video of behavior on tablet and tv can be found on 
https://github.com/ajaxspace/platfrom_view_sample_issue/tree/master/assets

<details>
  <summary>flutter doctor -v</summary>


<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
[✓] Flutter (Channel unknown, 2.0.4, on macOS 11.2.1 20D75 darwin-x64, locale en-US)
    • Flutter version 2.0.4 at /Users/yauheni_navakolski/fvm/versions/2.0.4
    • Framework revision b1395592de (5 weeks ago), 2021-04-01 14:25:01 -0700
    • Engine revision 2dce47073a
    • Dart version 2.12.2

[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0-rc1)
    • Android SDK at /Users/yauheni_navakolski/Library/Android/sdk
    • Platform android-30, build-tools 31.0.0-rc1
    • ANDROID_HOME = /Users/yauheni_navakolski/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5, Build version 12E262
    • CocoaPods version 1.10.1

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] IntelliJ IDEA Community Edition (version 2019.3.2)
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart

[✓] Connected device (3 available)
    • SM P610 (mobile) • R52N70QWRZT • android-arm64  • Android 10 (API 29)
    • macOS (desktop)  • macos       • darwin-x64     • macOS 11.2.1 20D75 darwin-x64
    • Chrome (web)     • chrome      • web-javascript • Google Chrome 90.0.4430.93

• No issues found!
```

</details>