Builders with shards have been consuming extra trigger bots, and waste lots of resources when rerunning (have to rerun all shards even a single subshard fails). Additionally it has caused difficulty to view results via LUCI UI: #64208.

This is tracking the process to separate shards into separate builders.

Try:

• Create separate builder configs for builders (with shards)
• Enable new separate builders in try_builder.json for presubmit
• Remove old builders (with shards) from try_builder.json for presubmit
• clean up configs for old try builders (with shards) (keep for a couple of days before removing, in case failures if not rebased)

Prod:

• Create separate builder configs for builders (with shards)
• Enable new separate builders in prod_builder.json for postsubmit
• Remove old builders (with shards) from prod_builder.json for postsubmit
• clean up configs for old builders (with shards)