test: fix flaky test-force-repl-with-eval

Remove the timer just in case the test takes longer to complete.

PR-URL: https://github.com/nodejs/node/pull/9460


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>