crypto: fix missing nullptr check on RSA_new()

Not checking this can cause a null deref. Since there is already a
null check at the bottom of the function with `NewRSA()`.

Author: ndossche

src/crypto/crypto_rsa.cc

@@ -385,6 +385,8 @@ KeyObjectData ImportJWKRsaKey(Environment* env,
   KeyType type = d_value->IsString() ? kKeyTypePrivate : kKeyTypePublic;
 
   RSAPointer rsa(RSA_new());
+  if (!rsa) return {};
+
   ncrypto::Rsa rsa_view(rsa.get());
 
   ByteSource n = ByteSource::FromEncodedString(env, n_value.As<String>());