This reverts commit 22b56f47.

Reason for revert: Speculatively reverting because it increases Android binary size unexpectedly, see https://ci.chromium.org/p/chromium/builders/luci.chromium.try/android-binary-size/72572

Original change's description:
> [snapshot] Factor out root serialization code
> 
> Factors out a new method Serializer::SerializeRoot which attempts to
> serialize a given object as a Root if it is one and the Serializer's
> policy allows that root to be serialized (implemented as a new virtual
> method RootCanBeSerialized)..
> 
> This is in preparation for adding a ReadOnlySerializer which change the
> way read-only roots are serialized.
> 
> Bug: v8:8191
> Change-Id: I7fbb4e9520fba8b836a0b6bf95ca39abc3ded79e
> Reviewed-on: https://chromium-review.googlesource.com/c/1264698
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Commit-Queue: Dan Elphick <delphick@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#56494}

TBR=jgruber@chromium.org,delphick@chromium.org,ygg@google.com

Change-Id: I7012abec0f33f655efc64dc44f7fa461d7e4b7e9
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:8191
Reviewed-on: https://chromium-review.googlesource.com/c/1273098Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56509}