Fix stale root error in verifier

There was a stale root error caused by the static roots from
the reg types. These were visitied if there was an active verifier
in the method_verifiers_ but this is not always the case when a GC
is run. The fix is to always visit the static method verifier roots.

This only showed up as a bug without an image since these roots
were primitive classes and always in the image, and therefore
didn't ever need to be updated due to moving GC.

(cherry picked from commit 6167864e)

Change-Id: I592f2770570de97b431671cfbd409f63697892f1