The wasm engine is the same for all units, thus we should store (or
get) it in the compilation task, and not store it duplicated in each
compilation unit.

R=mstarzinger@chromium.org

Bug: v8:8916, v8:8343
Change-Id: Id4b062b5b8a52228b4d6051a67e025088a61d466
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1559863
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60754}