Add warning timeout for tests that run >1min
This makes it easier to identify hanging tests. As described in #2873,
when a test doesn't finish, we so far had no information on which test
that was. In this PR, we add a duration of 60 seconds for each test,
after which a warning will be printed mentioning that this specific test
has been running for a long time already.
Example output:
https://gist.github.com/futile/6ea3eed85fe632df8633c1b03c08b012
r? @brson
ae77410350