This commit backports a fix to a crankshaft bug affects arm64 systems.

Original commit message:

    [arm64] Fix jssp based spill slot accesses in Crankshaft

    Review URL: https://codereview.chromium.org/1401703003

    Cr-Commit-Position: refs/heads/master@{#31304}

Fixes: #7417
PR-URL: #7442
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

This LTS release comes with 89 commits. This includes 46 commits that
are docs related, 11 commits that are test related, 8 commits that are
build related, and 4 commits that are benchmark related.

Notable Changes:

- debugger:
  - All properties of an array (aside from length) can now be printed
    in the repl (cjihrig)
    #6448
- npm:
  - Upgrade npm to 2.15.8 (Rebecca Turner)
    #7412
- stream:
  - Fix for a bug that became more prevalent with the stream changes
    that landed in v4.4.5. (Anna Henningsen)
    #7160
- V8:
  - Fix for a bug in crankshaft that was causing crashes on arm64
    (Myles Borins)
    #7442
  - Add missing classes to postmortem info such as JSMap and JSSet
    (evan.lucas)
    #3792

This LTS release comes with 89 commits. This includes 46 commits that
are docs related, 11 commits that are test related, 8 commits that are
build related, and 4 commits that are benchmark related.

Notable Changes:

- debugger:
  - All properties of an array (aside from length) can now be printed
    in the repl (cjihrig)
    #6448
- npm:
  - Upgrade npm to 2.15.8 (Rebecca Turner)
    #7412
- stream:
  - Fix for a bug that became more prevalent with the stream changes
    that landed in v4.4.5. (Anna Henningsen)
    #7160
- V8:
  - Fix for a bug in crankshaft that was causing crashes on arm64
    (Myles Borins)
    #7442
  - Add missing classes to postmortem info such as JSMap and JSSet
    (evan.lucas)
    #3792