Summary

Currently, task and variant are required flags for the perfcomp compare function. However, we are able to get this information by querying the raw_results collection for the most recent performance results for a specific project. We should change the required flags to instead by default get the first task/variant of the project's raw results and use that for filtering, and keep task and variant as optional flags.

Motivation

This decreases the number of required flags and makes it more straightforward to use so developers don't need to look for the task/variant names.

Acceptance Criteria

Task and variant become optional flags, instead defaulting to most recent task/variant of the project.