If a single background thread generates more code than
{kMaxCodeSpaceSize}, we cannot add them as one chunk. This CL adds a
CHECK to guard against that. If we find that this CHECK is hit in the
wild, we need to fix this for real.

R=ahaas@chromium.org

Bug: v8:11339
Change-Id: I549ecd79747bdf14a65b297c01779953e053abf2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2643382Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72247}