[engine] difficult to separate logs from tasks

[godofredoc]

The fuchsia test runner script does not print any logs to separate the different steps. This makes really difficult to identify if the builder failed because the paving process failed or if the device didn't come back after paving.

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.