* ci(studio): run the pull request edit accuracy slice in 10 shards
* ci(studio): run the pull request edit accuracy slice in 15 shards
* ci(studio): pack edit accuracy shards by measured case time so they finish together
* ci(studio): load shard timings with require so happy-dom tests can import the grid
* ci(studio): the slow runner stop judges runner speed, not how long a shard's first cases are
* ci(studio): keep the slow runner comment on one line under 120 characters