test: pause child until parent is ready

Pause child on startup using inspect-brk=0 until the parent debugger
is ready.

PR-URL: https://github.com/nodejs/node/pull/15774
Fixes: https://github.com/nodejs/node/issues/14897


Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>