Revert "fix: error should be thrown (#1817)" (#1864)

This reverts commit e7a3489.

Author: alexander-fenster

src/root.js

@@ -98,10 +98,10 @@ Root.prototype.load = function load(filename, options, callback) {
         /* istanbul ignore if */
         if (!callback)
             return;
-        if (sync)
-            throw err;
         var cb = callback;
         callback = null;
+        if (sync)
+            throw err;
         cb(err, root);
     }