Update test cases

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/tests/opt-testcases/tls13-kex-modes.sh b/tests/opt-testcases/tls13-kex-modes.sh
index 55159b4..d66f79b 100755
--- a/tests/opt-testcases/tls13-kex-modes.sh
+++ b/tests/opt-testcases/tls13-kex-modes.sh
@@ -2251,7 +2251,7 @@
             -s "found pre_shared_key extension" \
             -s "Found PSK_EPHEMERAL KEX MODE" \
             -s "Found PSK KEX MODE" \
-            -s "Binder is not matched." \
+            -s "Invalid binder." \
             -S "Pre shared key found" \
             -S "No matched PSK or ticket"\
             -S "key exchange mode: psk$" \
@@ -2275,7 +2275,7 @@
             -s "found pre_shared_key extension" \
             -s "Found PSK_EPHEMERAL KEX MODE" \
             -s "Found PSK KEX MODE" \
-            -s "Binder is not matched." \
+            -s "Invalid binder." \
             -S "Pre shared key found" \
             -S "No matched PSK or ticket"\
             -S "key exchange mode: psk$" \