Port two specs from the source PR that no layer of the stack had picked
up. Both assert behaviour that is already implemented, they were simply
left without coverage:
- the EphemeralRunnerSet, not just the listener, is re-pointed at a
newly registered runner scale set;
- that re-pointing happens with no spec change on the
AutoscalingRunnerSet at all, which is why drift detection cannot be
keyed on metadata.generation: re-registration writes the scale set
ID as an annotation, and metadata changes do not bump generation.
Ported verbatim and passing unmodified.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>