.. which traces various stats (time, memory) related to the snapshot.
Due to various flag shuffles, it was broken as of Oct 2020, with some
line items reporting constant 0.

This also refactors --profile-deserialization and
--serialization-statistics s.t. the former only reports
deserialization times and the latter reports memory. Memory.json now
passes both flags.

Change-Id: I7dacbbbe9f7a667e0802d0f7a44703dc34524a4e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2854742
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74241}