test: remove message from assert.strictEqual()

Converted the 'message' argument values from the last two free socket
assert.strictEqual() calls to code comments as they fail to provide the
necessary details and values specific to why the test is failing. The
default message returned from the strictEqual() call should provide
sufficient details for debugging errors.

PR-URL: https://github.com/nodejs/node/pull/19525


Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>