arch: Stop using TheISA within the ISAs.

We know for sure what the ISA is, so there's no need for the
indirection.

Change-Id: I73ff04c50890d40a4c7f40caeee746b68b846cb3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18488
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

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>