systemc: Filter out an Info about delta cycles and pseudo timesteps.

systemc: Filter out an Info about delta cycles and pseudo timesteps.

In the Accellera implementation, every time a delta cycle is traced a
check is done to see if the user has been told what the pseudo timestep
is. To avoid doing that check over and over, we'll leave that out and
tell the verify.py to ignore that message in the reference output.

Change-Id: I825f05394dccf03e951d29561a11c3cc6d4bcda7
Reviewed-on: https://gem5-review.googlesource.com/c/12969
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>