Make it easier to parse the output assertion

Make it easier to parse the output assertion

Currently, when the list of outputs doesn't match the expected outputs,
grit just prints a big unreadable block of text. This change just makes
it much easier to parse that output and fix the offending expectations.

[cjhopman, 2014-09-16 01:26:23]

cjhopman@chromium.org changed reviewers:
+ thakis@chromium.org

[cjhopman, 2014-09-16 01:26:23]

thakis: *

[Nico, 2014-09-16 04:03:47]

lgtm

[Nico, 2014-09-16 04:04:00]

(let me know if you need me to land this)

[cjhopman, 2014-09-24 20:02:08]

On 2014/09/16 04:04:00, Nico (hiding) wrote:
> (let me know if you need me to land this)

Yeah, I'm not a grit committer so if you could land this that'd be great.