test: remove third param from assert.strictEqual

Removing third argument in calls to assert.strictEqual() so that the
values of the first two arguments are shown instead as this is more
useful for debugging.

Refs: https://nodejs.org/api/assert.html#assert_assert_strictequal_actual_expected_message

PR-URL: #19536
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

test/parallel/test-fs-mkdir-rmdir.js

@@ -31,8 +31,8 @@ fs.mkdir(d, 0o666, common.mustCall(function(err) {
   fs.mkdir(d, 0o666, common.mustCall(function(err) {
     assert.ok(err, 'got no error');
     assert.ok(/^EEXIST/.test(err.message), 'got no EEXIST message');
-    assert.strictEqual(err.code, 'EEXIST', 'got no EEXIST code');
-    assert.strictEqual(err.path, d, 'got no proper path for EEXIST');
+    assert.strictEqual(err.code, 'EEXIST');
+    assert.strictEqual(err.path, d);
 
     fs.rmdir(d, assert.ifError);
   }));