This removes two pointers to Histograms from the memory tracker. These
histograms are stored as part of the Isolate and their lifetime is also
coupled to the Isolate. We cannot bind the pointers but need to pass
them (or the Isolate) as a parameter instead.

R=clemensh@chromium.org
BUG=v8:7424

Change-Id: I6b141b924bd858234641d6603a25fcb08cdf40e3
Reviewed-on: https://chromium-review.googlesource.com/1140312
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54512}