Add an argument that makes stem TRACE output log to a file

In #30591 (moved), there is too much TRACE output for the Travis console.

We can log to a file, and tail instead.

But it would be nice to still have the test progress on the console.

Trac:
Parent Ticket: #30591 (moved)

added component::archived/stem owner::atagar parent::30591 priority::medium resolution::implemented severity::normal sponsor::31-can status::closed stem tor-ci-fail-sometimes type::enhancement labels

Setting as sponsor 31 can, because we use these jobs to make sure our refactoring works.

Trac:
Sponsor: N/A to Sponsor31-can

Thanks teor! Added this argument, to use it supply '--log-file /path/to/log' among the test arguments.

https://gitweb.torproject.org/stem.git/commit/?id=d92936c

Feel free to reopen if ya need anything else.

Trac:
Status: new to closed
Resolution: N/A to implemented

closed

mentioned in issue #30698 (closed)

mentioned in issue #30591 (moved)