Mark non-flaky test as such (#58112)

https://dart.googlesource.com/external/github.com/flutter/flutter/+/0cca3c1d62095e8d94b9d13714f586b852e0be4b
1 file changed
tree: 78e4c170c8da1cdedad0a096af1e58438b72892e
  1. commits.json