src: return undefined when validation err == 0

Extracted from the QUIC PR. Not specific to QUIC even if the
behavior is currently only used there.

Signed-off-by: James M Snell <jasnell@gmail.com>

PR-URL: #33107
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

Author: jasnell

src/node_crypto_common.cc

@@ -34,6 +34,7 @@ using v8::NewStringType;
 using v8::Null;
 using v8::Object;
 using v8::String;
+using v8::Undefined;
 using v8::Value;
 
 namespace crypto {
@@ -330,11 +331,15 @@ const char* X509ErrorCode(long err) {  // NOLINT(runtime/int)
 }
 
 MaybeLocal<Value> GetValidationErrorReason(Environment* env, int err) {
+  if (err == 0)
+    return Undefined(env->isolate());
   const char* reason = X509_verify_cert_error_string(err);
   return OneByteString(env->isolate(), reason);
 }
 
 MaybeLocal<Value> GetValidationErrorCode(Environment* env, int err) {
+  if (err == 0)
+    return Undefined(env->isolate());
   return OneByteString(env->isolate(), X509ErrorCode(err));
 }