subevalvar() incorrectly assumed that CTLESC bytes were present iff the
expansion was quoted. However, they are present iff various processing such
as word splitting is to be done later on.
Example:
v=@$e@$e@$e@
y="${v##*"$e"}"
echo "$y"
failed if $e contained the magic CTLESC byte.
Exp-run done by: pav (with some other sh(1) changes)
60f7eec450