testing: Load kdf plugin in all scenarios that require it

Once we use plugin-provided prf+() these won't work otherwise.

testing/tests/ikev2-stroke/rw-eap-sim-radius/hosts/carol/etc/strongswan.conf

@@ -1,5 +1,5 @@
 # /etc/strongswan.conf - strongSwan configuration file
 
 charon {
-  load = random nonce aes sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac stroke kernel-netlink socket-default fips-prf eap-sim eap-sim-file updown
+  load = random nonce aes sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf stroke kernel-netlink socket-default fips-prf eap-sim eap-sim-file updown
 }

testing/tests/ikev2-stroke/rw-eap-sim-radius/hosts/dave/etc/strongswan.conf

@@ -1,5 +1,5 @@
 # /etc/strongswan.conf - strongSwan configuration file
 
 charon {
-  load = random nonce aes sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac stroke kernel-netlink socket-default fips-prf eap-sim eap-sim-file updown
+  load = random nonce aes sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf stroke kernel-netlink socket-default fips-prf eap-sim eap-sim-file updown
 }

testing/tests/ikev2-stroke/rw-eap-sim-radius/hosts/moon/etc/strongswan.conf

@@ -1,7 +1,7 @@
 # /etc/strongswan.conf - strongSwan configuration file
 
 charon {
-  load = random nonce aes sha1 sha2 md5 pem pkcs1 curve25519 gmp x509 curl revocation hmac stroke kernel-netlink socket-default eap-radius updown
+  load = random nonce aes sha1 sha2 md5 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf stroke kernel-netlink socket-default eap-radius updown
 
   plugins {
     eap-radius {