tests: AArch64 Linux as quick regressions (instead of AArch32)

tests: AArch64 Linux as quick regressions (instead of AArch32)

NOTE: Following the discussion on the current patch review, some
regressions have been moved to the long list (realview64-simple-atomic
and realview64-simple-timing) in order to reduce computation time. These
should be moved back to the quick list as soon as we get more computing
power.

Change-Id: I07b98c968ad35bf4c7b3646cb72d870e6b07b0d6
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22686
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>