test: `buffer.write` with longer string scenario

Make sure longer strings are written up to the buffer end

Refs: https://github.com/nodejs/node/pull/32119

PR-URL: https://github.com/nodejs/node/pull/32123


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>