It has a performance cost, and as the comment says we should be doing
the better solution. We want to land this preparatory change on prod
while the rest is still on staging, so we should just skip it for now.
Skipping it will not affect regular fixed-output and input-addressed
derivations, which are the only ones prod would deal with upon getting
this code.
The main CA derivations support branch will revert this commit so it
still works.
2ee0068fdc