child_process: better spawn error message

Throw ERR_INVALID_ARG_VALUE when filename passed to spawn is empty.

Fixes: https://github.com/nodejs/node/issues/19235

PR-URL: https://github.com/nodejs/node/pull/19305


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>