Add -j and --timeout options to the execute phase of verify.py. The --timeout option is implemented using the timeout utility program which is assumed to be available on the host system. Python 3.3 added a timeout argument to the subprocess module which is an alternative approach, but then we would be dependent on python 3.3. -j is implemented using the standard multiprocess.pool.ThreadPool class. Change-Id: I15b92f2b14de6710e2027a6a19984b2644b2a8df Reviewed-on: https://gem5-review.googlesource.com/12051 Reviewed-by: Gabe Black <gabeblack@google.com> Maintainer: Gabe Black <gabeblack@google.com>