Update PR: return original error if formatted graphql error is empty

packages/gatsby/src/internal-plugins/query-runner/graphql-errors.js

@@ -175,25 +175,18 @@ export function graphqlError(
     )
   }
 
-  message = `There was an error while compiling your site's GraphQL queries.
-  ${message}
+  let reportedMessage = `There was an error while compiling your site's GraphQL queries.
+  ${message || error.message}
     `
+
   if (error.message.match(/must be an instance of/)) {
-    message +=
+    reportedMessage +=
       `This usually means that more than one instance of 'graphql' is installed ` +
       `in your node_modules. Remove all but the top level one or run \`npm dedupe\` to fix it.`
   }
 
   if (error.message.match(/Duplicate document/)) {
-    message += `${error.message.slice(21)}\n`
+    reportedMessage += `${error.message.slice(21)}\n`
   }
-
-  if (
-    process.env.gatsby_log_level === `verbose` &&
-    error.message.match(/GraphQLParser/)
-  ) {
-    message += `${error.message}`
-  }
-
-  return message
+  return reportedMessage
 }