Stack sorting safety

Use the defined typechecking stack method to sort the compression methods stack
rather than using the generic function and apply type casts.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4382)

fuzz/client.c

@@ -49,7 +49,7 @@ int FuzzerInitialize(int *argc, char ***argv)
     idx = SSL_get_ex_data_X509_STORE_CTX_idx();
     FuzzerSetRand();
     comp_methods = SSL_COMP_get_compression_methods();
-    OPENSSL_sk_sort((OPENSSL_STACK *)comp_methods);
+    sk_SSL_COMP_sort(comp_methods);
 
 
     return 1;

fuzz/server.c

@@ -496,7 +496,7 @@ int FuzzerInitialize(int *argc, char ***argv)
     idx = SSL_get_ex_data_X509_STORE_CTX_idx();
     FuzzerSetRand();
     comp_methods = SSL_COMP_get_compression_methods();
-    OPENSSL_sk_sort((OPENSSL_STACK *)comp_methods);
+    sk_SSL_COMP_sort(comp_methods);
 
 
     return 1;