stdlib: Add beta simulate module to the gem5 stdlib

This module is used to semi-automate the running of gem5 simulation,
mostly by handling exit events automatically and removing instantiation
boilerplate code.

NOTE: This module is still in beta.

Change-Id: I4706119478464efcf4d92e3a1da05bddd0953b6a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/50753
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
14 files changed