report: refactor argument validation

PR-URL: #26276
Reviewed-By: Richard Lau <[email protected]>
Reviewed-By: James M Snell <[email protected]>

Author: cjihrig

lib/internal/process/report.js

@@ -91,13 +91,13 @@ const report = {
   },
   getReport(err) {
     emitExperimentalWarning('report');
-    if (err == null) {
-      return nr.getReport(new ERR_SYNTHETIC().stack);
-    } else if (typeof err !== 'object') {
+
+    if (err === undefined)
+      err = new ERR_SYNTHETIC();
+    else if (err === null || typeof err !== 'object')
       throw new ERR_INVALID_ARG_TYPE('err', 'Object', err);
-    } else {
-      return nr.getReport(err.stack);
-    }
+
+    return nr.getReport(err.stack);
   }
 };