This CL changes `scheduleTask` to use a cached ObjectTemplate to
create the JS task objects. Console creates the template lazily upon
first use.

A local micro benchmark that creates 100k task objects shows a
speedup of roughly 4x.

R=jarin@chromium.org

Bug: chromium:1334585
Change-Id: Ice037ad32836fe428b1bcbee15738cb17877a3dd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3779496
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81906}