Ben Gamari authored Feb 26, 2019 and Marge Bot committed Mar 06, 2019

Now since we have been a bit more stringent in testsuite cleanliness we
have been marking a lot of tests as fragile using the `skip` modifier.
However, this unfortunately means that we lose the association with the
ticket number documenting the fragility.

Here we introduce `fragile` and `fragile_for` to retain this
information.