vcs-testharness has slow memory

Created by: cathales

Hello,

When we simulate Coremark using vcs-testharness, penalty of both instruction and data cache misses are significantly higher than using veri-testharness, by a factor of at least 4. This results in a poor measured performance in VCS.

# Will use veri-testharness as a default
bash verif/regress/coremark.sh
# Will use vcs-testharness instead
DV_SIMULATORS=vcs-testharness bash verif/regress/coremark.sh

Until now, we were only using veri-testharness to work on performance. CI uses veri-testharness for Coremark and Dhrystone.