test: update setTimeout on file test/internet/test-net-connect-unref.js to use common.platformTimeout

Hi!

This is my first PR 😄 I'm sorry if I make any mistake.

This commit updates the time used on the timeOut function to confonform to the recomendation given by the guide on writing tests.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines