This is a metabug to track our Q1 '18 efforts to make Findit get progress reports from tryjobs it triggers every time the regression range is narrowed down, surface this information to Sheriff-o-Matic, and use the narrowed revision ranges as suspects to new tryjobs created by Findit for failures in the same group.

The scope of this feature for this quarter is limited to:
- Changing the recipes so that they can generate partial reports after analyzing each revision
- Setting up an endpoint on Findit for the tryjobs to post these partial reports and persist them to the datastore
- Exposing the narrowest known regression range for ongoing analyses so that it can be displayed on SoM
- Add a metric in SoM to gauge the usage of this information (track when a sheriff expands this narrowed range)
- When triggering a new tryjob, if there are no heuristic-based suspects, use the narrowed revision range of the group (if any) as a hint.