Prettier would do this anyway, but it’s separated out for a more
reviewable diff. Generated by ESLint.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
We change the user facing interface to allow specifying expected
number of error messages (default=1). Now an average test can look
like:
```
// We expect 3 error messages;
blueslip.expect('error', 'an error message', 3);
throwError();
throwError();
throwError();
blueslip.reset();
```