Elide restoring of c for more commands
Elide restoring of c for more commands

atlimit, do, set and unset all leave c alone or restore its value, and
adding them improves codegen for several of the current stemmers.

snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball