V8 is capped by a maximum. Since the embedder step is computed from V8's
speeds using concurrent marking it may be too aggressive. Cap the
embedder step to the same maximum as V8 to workaround that issue.

Bug: chromium:1044630
Change-Id: Idcd84cacf2f3fa4dd8df2a03aa3ae6ffb6cb36a6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2062393Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66314}