Stop test & bench build failures with --disable-curve25519

Ensure test & bench code that references curve25519 is disabled by the
appropriate macros. tor now builds with and without --disable-curve25519.

changes/bug13285-disable-curve25519-build-errors

@@ -0,0 +1,3 @@
+  o Minor bugfixes:
+    - Stop test & bench build failures with --disable-curve25519.
+      Fixes bug 13285.

src/test/bench.c

@@ -236,7 +236,6 @@ bench_onion_ntor(void)
   ntor_handshake_state_free(state);
   dimap_free(keymap, NULL);
 }
-#endif
 
 static void
 bench_ed25519(void)
@@ -294,6 +293,7 @@ bench_ed25519(void)
   printf("Blind a public key: %.2f usec\n",
          MICROCOUNT(start, end, iters));
 }
+#endif
 
 static void
 bench_cell_aes(void)
@@ -575,8 +575,8 @@ static struct benchmark_t benchmarks[] = {
   ENT(onion_TAP),
 #ifdef CURVE25519_ENABLED
   ENT(onion_ntor),
-#endif
   ENT(ed25519),
+#endif
   ENT(cell_aes),
   ENT(cell_ops),
   ENT(dh),

src/test/test_crypto.c

@@ -13,9 +13,9 @@
 #include "siphash.h"
 #ifdef CURVE25519_ENABLED
 #include "crypto_curve25519.h"
+#endif
 #include "crypto_ed25519.h"
 #include "ed25519_vectors.inc"
-#endif
 #include "crypto_s2k.h"
 #include "crypto_pwbox.h"
 
@@ -1697,8 +1697,6 @@ test_crypto_ed25519_test_vectors(void *arg)
   tor_free(mem_op_hex_tmp);
 }
 
-#endif
-
 static void
 test_crypto_ed25519_encode(void *arg)
 {
@@ -1875,6 +1873,7 @@ test_crypto_ed25519_testvectors(void *arg)
  done:
   tor_free(mem_op_hex_tmp);
 }
+#endif /* CURVE25519_ENABLED */
 
 static void
 test_crypto_siphash(void *arg)