Rather, ditto for the env vars -- when linewise is being tested for, have the test be "linewise or parallel".
Realistically, linewise shouldn't even be an exposed option as it's almost never going to be useful except in parallel mode; but now that it's out, it can't hurt to leave it as-is so folks can use it if they want.
The inverse, forcing bytewise parallelism, strikes me as an unusual case that can be safely ignored until somebody specifically asks for it.
Rather, ditto for the env vars -- when linewise is being tested for, have the test be "linewise or parallel".
Realistically, linewise shouldn't even be an exposed option as it's almost never going to be useful except in parallel mode; but now that it's out, it can't hurt to leave it as-is so folks can use it if they want.
The inverse, forcing bytewise parallelism, strikes me as an unusual case that can be safely ignored until somebody specifically asks for it.