text: Title: Consider removing saveCompilationTrace
  Body: `dart:ui` exposes [saveCompilationTrace](https://api.flutter.dev/flutter/dart-ui/saveCompilationTrace.html), which, according to @jonahwilliams, is:
  
  > completely unused (and unusable) by the framework so we should probably file a bug to remove it
  
  Source: https://github.com/flutter/engine/pull/18933#discussion_r438408808
  