arch-arm: Add support for Tarmac trace generation

This patch introduces the TarmacTracer: an instruction tracer which
allows to dump a gem5 execution trace in Tarmac format [1]. The new
tracer is supporting either Tarmac and TarmacV8 format specifications.
Not every traceable information has been implemented:

Implemented Trace Type:
Instruction Trace
Register Trace
Processor Memory Access Trace

Unimplemented Trace Type:
Program Flow Trace
Event Trace
Memory Bus Trace

[1]: https://developer.arm.com/docs/dui0845/f/tarmac-trace-file-format

Change-Id: I8799d8e5852e868673f728971db3fe8c63961f5e
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/9382
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-arm: Add support for Tarmac trace-based simulation

A new InstTracer (TarmacParser) has been implemented. This tracer is
parsing a pre-existing Tarmac trace file [1] while gem5 is running; it
is comparing execution data together with trace data and it is dumping
differences.
This allows to use Tarmac format as a glue between heterogeneous
simuators speaking the same Tarmac language.

Kudos to Giacomo Gabrielli for writing the original tracer.

[1]: https://developer.arm.com/docs/dui0845/f/tarmac-trace-file-format

Change-Id: I9b92204a149813166166adba4a7c61a248bdcac3
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/9381
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>