max concurrency is inferred from queue size for OLD_SPACE & MAP_SPACE.
Extra Sweeper::TearDown() in MarkCompactCollector::TearDown() is needed
to cancel job.

Change-Id: Iafba7d7d24e8f6e5c5a1d5c0348dea731f0ac224
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2480783
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70767}