test: add --abort-on-timeout option to test.py

Currently, when a process times out, it is terminated by sending it the
SIGTERM signal. Sending SIGBART instead allows the operating system to
generate a core file that can be investigated later using post-mortem
debuggers such as llnode or mdb_v8.

This can be very useful when investigating flaky tests that time out,
since in that case the failure is difficult to reproduce, and being able
to look at a core file makes a big difference.

With these changes, passing the --abort-on-timeout command line option
to tools/test.py now sends SIGABRT to processes timing out on all
platforms but Windows.

PR-URL: https://github.com/nodejs/node/pull/11086
Ref: https://github.com/nodejs/node/issues/11026


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>