[WIP] feat: cram tests that timeout now offer partial promotion

[benodiwal]

Closes #12343

NOTE: Deleted timeout-no-command.t as it tested the old behavior (timeouts not showing which command failed). This is now covered by the new timeout-partial-promotion.t test.

[benodiwal]

Require some input on the direction and the output present in test files.

[Alizter]

This is a good start but I would rather that the error semantics for a timed out cram test are preserved. Essentially such a failing cram test would produce two errors where one is a diff and the other is a timeout.

I have a WIP branch here https://github.com/Alizter/dune/tree/push-oowqxypwmrtn which I haven't had time to rebase recently. It involves a number of changes but mainly adds locations to the cram error messages, offers partial promotions and allows for both diffs and errors to be raised together.

I do plan to come back to this but I don't want to stop you from making progress here, so please feel free to inspect the branch and pick out anything that will help you improve this PR. The tests there are also worth reading so that you can get an idea of the semantics I was going for.