■Symptoms:
　(I think this issue is highly related to #23496. If this new issue is inappropriate to create, I'm sorry)
　Emojis have multiple cursor positions.
　If I delete emoji, bug like issue 23496 still happens.
　If I input single alphabet character on the middle cursor of the Emoji cursor,
　also same bug happens like issue 23496.

■Symptoms example video:
　https://twitter.com/LainNao/status/1231695776465608706

■Environment:
・Flutter doctor：
　Doctor summary (to see all details, run flutter doctor -v):
　[√] Flutter (Channel master, v1.14.7-pre.118, on Microsoft Windows [Version 10.0.19541.1000], locale ja-JP)

　[√] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
　[√] Chrome - develop for the web
　[√] Android Studio (version 3.5)
　[√] VS Code (version 1.42.1)
　[√] Connected device (2 available)

　• No issues found!
・Keyboard: "GBoard" or "iWnn IME日本語"
・SystemLanguage: Japanese
・OS: EMUI 9.1.0
・Device: HUAWEI P30 lite
・Android version: 9