Use a relative path for the output when building a Dart kernel (#28847)

https://dart.googlesource.com/external/github.com/flutter/engine/+/5f7d0053f98dd5284f69514504e8b0f318ac9f13
1 file changed
tree: da0c39a2668de7117c4a14a516401e1e4db335de
  1. commits.json