[spec 9] QuickJS: hand off at the invocation deadline #5168

(AI) Follow-up from #4661 (spec 9, the experimental single-orchestrator runtime, opt-in via WORKFLOW_SPEC_VERSION=9). Tracked as follow-up 15 on the spec 9 changelog.

The QuickJS orchestrator does not hand off when an inline step runs past the invocation deadline, and it starts the next inline step after it: the adapter contract test sees both of a run's slow inline steps run in one delivery that the node engine hands off after the first. On world-vercel such a delivery can run into the function's maximum duration. Apply the node engine's deadline check and inline-start margin to the QuickJS loop.