Fix zgrep(1) wrapper regression, add test

@bdrewery reported D48873 broke "bzgrep -q '1 2' /var/log/messages.0.bz2"
The mistake was in using $* instead of "$@" (I suspect $* is never right).

Reported by: bdrewery
Reviewed by: markj
Approved by: markj
Fixes: 1070477cc8b7 ("Fix remaining zgrep(1) wrapper script regressions")
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D54217