Starting marking required Creating a Marker and calling StartMarking.
StartMarking should always have been called immediately after creating
the marker.
Since markers are not persisted between GC (a marker exists only while
marking is in progress), it makes sense to start marking implicitly when
a marker is created.

Calling StartMarking in MarkerBase ctor is inadvisable since subclasses
might still to initialize fields.
Using MarkerFactory instead guarantees that StartMarking is always
called immediately after creating a Marker.

Bug: chromium:1056170
Change-Id: Icbf11afd848e1618c204ca6bf951600b3ae9fef2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2375199
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69601}