Use track-widget-creation transformer included in the sdk. (#9085)

This improves performance as the version in the SDK is able to work more
incrementally and avoids creating an expensive ClassHierarchy.
There is now no measureable performance difference with the option so the
kernel transformer can be enabled by default.
https://dart.googlesource.com/external/github.com/flutter/engine/+/651c90409ee7b8f43da7d1c60fcb172f1ad51901
1 file changed
tree: ebbbcc4090b08da4d7f41a1874cac5c39c012de3
  1. commits.json