src: guard against env != null in node_errors.cc

Otherwise
`TriggerUncaughtException()`
→ `PrintException()`
→ `GetErrorSource()`
can crash.

PR-URL: #36414
Reviewed-By: Michaël Zasso <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Shelley Vohr <[email protected]>
Reviewed-By: Rich Trott <[email protected]>

Author: addaleax

src/node_errors.cc

@@ -63,7 +63,7 @@ static std::string GetErrorSource(Isolate* isolate,
   Environment* env = Environment::GetCurrent(isolate);
   const bool has_source_map_url =
       !message->GetScriptOrigin().SourceMapUrl().IsEmpty();
-  if (has_source_map_url && env->source_maps_enabled()) {
+  if (has_source_map_url && env != nullptr && env->source_maps_enabled()) {
     return sourceline;
   }