ssl-opt.sh: Add a check of the list of supported ciphersuites

Signed-off-by: Ronald Cron <ronald.cron@arm.com>

tests/ssl-opt.sh

@@ -358,9 +358,18 @@ requires_protocol_version() {
 
 # Space-separated list of ciphersuites supported by this build of
 # Mbed TLS.
-P_CIPHERSUITES=" $($P_CLI help_ciphersuites 2>/dev/null |
-                   grep 'TLS-\|TLS1-3' |
-                   tr -s ' \n' ' ')"
+P_CIPHERSUITES=""
+if [ "$LIST_TESTS" -eq 0 ]; then
+    P_CIPHERSUITES=" $($P_CLI help_ciphersuites 2>/dev/null |
+                       grep 'TLS-\|TLS1-3' |
+                       tr -s ' \n' ' ')"
+
+    if [ -z "${P_CIPHERSUITES# }" ]; then
+        echo >&2 "$0: fatal error: no cipher suites found!"
+        exit 125
+    fi
+fi
+
 requires_ciphersuite_enabled() {
     case $P_CIPHERSUITES in
         *" $1 "*) :;;