lib: ensure --check flag works for piped-in code

Previously, the --check CLI flag had no effect when run on code piped
from stdin. This commit updates the bootstrap logic to handle the
--check flag the same way regardless of whether the code is piped from
stdin.

PR-URL: https://github.com/nodejs/node/pull/11689
Fixes: https://github.com/nodejs/node/issues/11680


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>