test: remove string literal from assertion

Remove string literal as assertion message in call to
assert.strictEqual() in test-dns-lookup.
Backport-PR-URL: #22912
PR-URL: #22849
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: Trott

test/parallel/test-dns-lookup.js

@@ -134,8 +134,8 @@ dns.lookup('example.com', common.mustCall((error, result, addressType) => {
 assert.strictEqual(tickValue,1);
 assert.strictEqual(error.code,'ENOENT');
 constdescriptor=Object.getOwnPropertyDescriptor(error,'message');
-assert.strictEqual(descriptor.enumerable,
-false,'The error message should be non-enumerable');
+// The error message should be non-enumerable.
+assert.strictEqual(descriptor.enumerable,false);
 }));
 
 // Make sure that the error callback is called