crypto: fix error condition in Verify::VerifyFinal

Fail early if key parsing failed, don't try to construct a context out
of it.

PR-URL: #26238
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

src/node_crypto.cc

@@ -4648,6 +4648,8 @@ void Verify::VerifyFinal(const FunctionCallbackInfo<Value>& args) {
 
   unsigned int offset = 0;
   ManagedEVPPKey pkey = GetPublicOrPrivateKeyFromJs(args, &offset, true);
+  if (!pkey)
+    return;
 
   char* hbuf = Buffer::Data(args[offset]);
   ssize_t hlen = Buffer::Length(args[offset]);