Output format is supposed to be

// <*>RESULT <graph_name>: <trace_name>= {<mean>, <std deviation>} <units>

where graph_name = metric and trace_name = story. Many tests have metric and story switched.

Wrote this to catch low-hanging fruit: https://chromium-review.googlesource.com/c/chromium/src/+/1423673

media_perftests seems fine. Seems like we just need to fix https://bugs.chromium.org/p/chromium/issues/detail?id=918601#c16
so that it always outputs with _biggerIsBetter or _smallerIsBetter

Brian, for a line like this
*RESULT clockless_video_playback_vp8: bear_silent.webm= 53.406108056578425 runs/s

do we want to modify to 

A.
*RESULT clockless_video_playback_vp8: bear_silent.webm= 53.406108056578425 runs/s_biggerIsBetter

or 

B.
*RESULT clockless_video_playback_vp8_biggerIsBetter: bear_silent.webm= 53.406108056578425 runs/s

?