Depends on D20219. Ref T13258. Ref T11415. Installs sometimes have long-running builds or unimportant builds which they may not want to hold up drafts, affect buildable status, or warn during `arc land`.
Some builds have side effects (like deployment or merging) and are not idempotent. They can cause problems if restarted.
In other cases, builds are isolated an idempotent and generally safe, and it's okay for marketing interns to restart them.
To address these cases, add "Behaviors" to Build Plans:
- Hold Drafts: Controls how the build affects revision promotion from "Draft".
- Warn on Land: Controls the "arc land" warning.
- Affects Buildable: Controls whether we care about this build when figuring out if a buildable passed or failed overall.
- Restartable: Controls whether this build may restart or not.
- Runnable: Allows you to weaken the requirements to run the build if you're confident it's safe to run it on arbitrary old versions of things.
NOTE: This only implements UI, none of these options actually do anything yet.