t/test-lib-functions.sh: avoid "test <cond> -a/-o <cond>"

The construct is error-prone; "test" being built-in in most modern
shells, the reason to avoid "test <cond> && test <cond>" spawning
one extra process by using a single "test <cond> -a <cond>" no
longer exists.

Signed-off-by: Elia Pinto <gitter.spiros@gmail.com>
Reviewed-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/test-lib-functions.sh

@@ -542,7 +542,7 @@ test_must_fail () {
 	if test $exit_code = 0; then
 		echo >&2 "test_must_fail: command succeeded: $*"
 		return 1
-	elif test $exit_code -gt 129 -a $exit_code -le 192; then
+	elif test $exit_code -gt 129 && test $exit_code -le 192; then
 		echo >&2 "test_must_fail: died by signal: $*"
 		return 1
 	elif test $exit_code = 127; then
@@ -569,7 +569,7 @@ test_must_fail () {
 test_might_fail () {
 	"$@"
 	exit_code=$?
-	if test $exit_code -gt 129 -a $exit_code -le 192; then
+	if test $exit_code -gt 129 && test $exit_code -le 192; then
 		echo >&2 "test_might_fail: died by signal: $*"
 		return 1
 	elif test $exit_code = 127; then