*Scan: Introduce StateBitmap

StateBitmap aims to replace existing quarantine bitmaps. The goal of the
new bitmap is to store more context for allocations. This helps the
scanner to check if a block is freed, allocated or quarantined. Not
scanning freed blocks help *Scan to avoid redundant page faults. At the
same time, this makes the clearing phase redundant (after the
QuarantineCardTable is gone).

More details are in the design doc: https://shorturl.at/muEUW

Bug: 1237828,11297512

Change-Id: I4d5ef2211f2799e3ee16e107d91f6ec0e4fd6234
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3071364


Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#910221}