Adds two regression tests for #8234 that the existing suite does not cover:
- an OPT-less upstream reply that carries a record, so the per-record
response rules run while the request OPT is reused by ScrubWriter;
- a request that already carries the option, where "set ... revert" must
put the client's original value back rather than just drop the option.
Both fail against the tree before #8235 and pass on current master.
Signed-off-by: maximilize <3752128+maximilize@users.noreply.github.com>
