They are only needed in the async DecodeModule step. We can just store
a raw pointer to the Counters there.

R=mstarzinger@chromium.org

Bug: v8:8238
Change-Id: I2b22008fc4cbf6f8f69c9d53822fdb5af7d638f6
Reviewed-on: https://chromium-review.googlesource.com/c/1303302
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57078}