Do not check fail cases for verify skipped

In testcases where we are expecting handshake failure the message
"Certificate verification was skipped" is not printed, so do not check
for it.

Signed-off-by: David Horstmann <david.horstmann@arm.com>

tests/opt-testcases/tls13-kex-modes.sh

diff --git a/tests/opt-testcases/tls13-kex-modes.sh b/tests/opt-testcases/tls13-kex-modes.sh
index f0984c5..a886455 100644
--- a/tests/opt-testcases/tls13-kex-modes.sh
+++ b/tests/opt-testcases/tls13-kex-modes.sh
@@ -526,8 +526,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_gnutls_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -593,8 +592,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_gnutls_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -687,8 +685,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_gnutls_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -757,8 +754,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_gnutls_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -804,8 +800,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_gnutls_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -873,8 +868,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_gnutls_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -918,8 +912,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_gnutls_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -1381,8 +1374,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -1445,8 +1437,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -1512,8 +1503,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -1579,8 +1569,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
@@ -1645,8 +1634,7 @@
             -s "Invalid binder." \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
-            -S "key exchange mode: ephemeral" \
-            -s "! Certificate verification was skipped"
+            -S "key exchange mode: ephemeral"
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3