syscall_emul: [patch 14/22] adds identifier system calls

This changeset add fields to the process object and adds the following
three system calls: setpgid, gettid, getpid.

syscall_emul: [patch 5/22] remove LiveProcess class and use Process instead

The EIOProcess class was removed recently and it was the only other class
which derived from Process. Since every Process invocation is also a
LiveProcess invocation, it makes sense to simplify the organization by
combining the fields from LiveProcess into Process.

tests: Update SMT tests to correctly configure CPUs

The 01.hello-2T-smt test case for the O3 CPU didn't correctly setup
the number of threads before creating interrupt controllers, which
confused the constructor in BaseCPU. This changeset adds SMT support
to the test configuration infrastructure.

config,cpu: Add SMT support to Atomic and Timing CPUs

Adds SMT support to the "simple" CPU models so that they can be
used with other SMT-supported CPUs. Example usage: this enables
the TimingSimpleCPU to be used to warmup caches before swapping to
detailed mode with the in-order or out-of-order based CPU models.

config: Add a BaseSESystem builder for re-use in regressions

This patch extends the existing system builders to also include a
syscall-emulation builder. This builder is deployed in all
syscall-emulation regressions that do not involve Ruby,
i.e. o3-timing, simple-timing and simple-atomic, as well as the
multi-processor regressions o3-timing-mp, simple-timing-mp and
simple-atomic-mp (the latter are only used by SPARC at this point).

The values chosen for the cache sizes match those that were used in
the existing config scripts (despite being on the large
side). Similarly, a mem_class parameter is added to the builder base
class to enable simple-atomic to use SimpleMemory and o3-timing to use
the default DDR3 configuration.

Due to the different order the ports are connected, the bus stats get
shuffled around for the multi-processor regressions. A separate patch
bumps the port indices. Besides this, all behaviour is exactly the
same.

SE/FS: Make both SE and FS tests available all the time.