Provide a global memory controller used to compute limits for combined
on-heap and embedder memory. The global controller uses the same
mechanism (gc speed, mutator speed) and growing factors as the regular
on-heap controller.

Rely on V8's mechanisms for configured state that stops shrinking the
limit.

Reland:
- API fixes with overrides and default versions.
- Fix of depending on uninitialized values when using the old API.
- GCTracer: Fixed issue in speed computation.
- GCTracer: Added unittests.

This reverts commit 5e043f27.

Bug: chromium:948807
Change-Id: I0f81253b3e1a8b49a7ac107c012a15e33cb514d7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1622852Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61735}