deps: cherry-pick e0d64dc from upstream V8

Original commit message:

    [heap] Print the number of chunks in unmapper queue in --trace-gc-nvp

    Bug: chromium:771966
    Change-Id: I146b279c4713b7dd716c6d55ca5e6c6e23a3ad7e
    Reviewed-on: https://chromium-review.googlesource.com/704740


Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
    Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#48338}

Refs: https://github.com/v8/v8/commit/e0d64dc67c6abf36a37efdc6e8e6903bb114ebd3
Refs: https://github.com/nodejs/help/issues/917#issuecomment-339292642
Refs: https://bugs.chromium.org/p/chromium/issues/detail?id=771966

PR-URL: https://github.com/nodejs/node/pull/16490


Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>