fix bashisms in testsuite/

These places use ${var/search/replace}, $((n++) and
`type -p' constructs which are not-so-standard.
Replace with equivalent constructs.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

testsuite/testing.sh

@@ -56,10 +56,10 @@ optional()
 {
 	SKIP=
 	while test "$1"; do
-		if test x"${OPTIONFLAGS/*:$1:*/y}" != x"y"; then
-			SKIP=1
-			return
-		fi
+		case "${OPTIONFLAGS}" in
+			*:$1:*) ;;
+			*) SKIP=1; return ;;
+		esac
 		shift
 	done
 }