test-lint: only use only sed [-n] [-e command] [-f command_file]

From `man sed` (on a Mac OS X box):
The -E, -a and -i options are non-standard FreeBSD extensions and may not be available
on other operating systems.

From `man sed` on a Linux box:
REGULAR EXPRESSIONS
       POSIX.2 BREs should be supported, but they aren't completely because of
       performance problems.  The \n sequence in a regular expression matches the newline
       character,  and  similarly  for \a, \t, and other sequences.
       The -E option switches to using extended regular expressions instead; the -E option
       has been supported for years by GNU sed, and is now included in POSIX.

Well, there are still a lot of systems out there, which don't support it.
Beside that, IEEE Std 1003.1TM-2017, see
http://pubs.opengroup.org/onlinepubs/9699919799/
does not mention -E either.

To be on the safe side, don't allow -E (or -r, which is GNU).
Change check-non-portable-shell.pl to only accept the portable options:
sed [-n] [-e command] [-f command_file]

Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/check-non-portable-shell.pl

@@ -35,7 +35,7 @@ while (<>) {
 		chomp;
 	}
 
-	/\bsed\s+-i/ and err 'sed -i is not portable';
+	/\bsed\s+-[^efn]\s+/ and err 'sed option not portable (use only -n, -e, -f)';
 	/\becho\s+-[neE]/ and err 'echo with option is not portable (use printf)';
 	/^\s*declare\s+/ and err 'arrays/declare not portable';
 	/^\s*[^#]\s*which\s/ and err 'which is not portable (use type)';