arm: pmu: Add tests for 64-bit overflows

Modify all tests checking overflows to support both 32 (PMCR_EL0.LP == 0)
and 64-bit overflows (PMCR_EL0.LP == 1). 64-bit overflows are only
supported on PMUv3p5.

Note that chained tests do not implement "overflow_at_64bits == true".
That's because there are no CHAIN events when "PMCR_EL0.LP == 1" (for more
details see AArch64.IncrementEventCounter() pseudocode in the ARM ARM DDI
0487H.a, J1.1.1 "aarch64/debug").

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Andrew Jones <andrew.jones@linux.dev>