test: change test to not be sensitive to buffer send size

Change the test to not be sensitive to the buffer size causing
TCP resets to be received by the client causing the test to fail.
The test now reads the entire expected buffer and then checks for
the expected event to fire.

PR-URL: https://github.com/nodejs/node/pull/31499


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>