assert: remove unneeded condition

PR-URL: #11314
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

Author: Trott

lib/assert.js

@@ -291,7 +291,8 @@ assert.notStrictEqual = function notStrictEqual(actual, expected, message) {
 };
 
 function expectedException(actual, expected) {
-  if (!actual || !expected) {
+  // actual is guaranteed to be an Error object, but we need to check expected.
+  if (!expected) {
     return false;
   }