This is needed to allow deriving timeout and near_timeout runnables on the
recipe side and drop corresponding fields in the output.

We also remove some unused code that was removed in previous refactoring CLs.

R=tmrts@chromium.org

No-Try: true
No-Tree-Checks: true
Bug: chromium:841700
Change-Id: Ib7cec9baceff994fb9b32be09ba4a4079ebff2c8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1588417
Commit-Queue: Sergiy Belozorov <sergiyb@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61095}