tests: Use MatchFileRegex vierifier for realview regressions
tests: Use MatchFileRegex vierifier for realview regressions

We have seen cases where the primary CPU was not able to bootstrap the
secondary CPUs in multicore tests (dual). The Linux booting process
"quietly" gives up (no panic) and it completes the booting without
bringing up the seondary CPU(s). This makes the dual test useless as it
is supposed to test SMP setups.

By adding a MatchFileRegex verifier, we make sure we are able to catch
these cases, correctly raising an error if not all CPUs are available.
We do this by inspecting the kernel log for the following print:

"CPU1: Booted secondary processor"

There are probably more resilient alternatives to a regex based check,
but those require a less minimal rootfs (the current
m5_exit.squashfs.arm64 FS has a single /sbin/init binary executing a
simple m5 exit operation)

Signed-off-by: Giacomo Travaglini <8eef13a4f970e2e9372c8d26ad0737b760f99c02@arm.com>
Change-Id: I37e0882967443449d5fedfe3963bd25528a030f8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/44446
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Daniel Carvalho <91779fc734d358d9575ec4910de29bfcbcaf1b22@yahoo.com.br>
Reviewed-by: Jason Lowe-Power <92de577f37050ad05b60626d2f17913f40dcb1a2@gmail.com>
Maintainer: Jason Lowe-Power <92de577f37050ad05b60626d2f17913f40dcb1a2@gmail.com>

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