build: fix benchmark tests on CI

PR-URL: https://github.com/nodejs/node/pull/24307
Refs:
https://github.com/nodejs/build/issues/1568#issuecomment-437681599


Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>