edithtml.sh: make tests portable to any correct POSIX shell.
edithtml.sh: make tests portable to any correct POSIX shell.

Signed-off-by: Daira Hopwood <cd7d43d5556a38ce626d53826fddc46adc597539@jacaranda.org>

zcash/zips,zcash/zips,zcash/zips,zcash/zips