8199161: Better interface enumeration

Reviewed-by: igerasim, mschoene, michaelm, rhalade

src/windows/native/java/net/NetworkInterface.c

@@ -861,6 +861,7 @@ JNIEXPORT jobjectArray JNICALL Java_java_net_NetworkInterface_getAll
     /* allocate a NetworkInterface array */
     netIFArr = (*env)->NewObjectArray(env, count, cls, NULL);
     if (netIFArr == NULL) {
+        free_netif(ifList);
         return NULL;
     }
 
@@ -875,6 +876,7 @@ JNIEXPORT jobjectArray JNICALL Java_java_net_NetworkInterface_getAll
 
         netifObj = createNetworkInterface(env, curr, -1, NULL);
         if (netifObj == NULL) {
+            free_netif(ifList);
             return NULL;
         }