This is a reland of b66993bc

Nothing changed in the reland, the original CL was not the
culprit for win32 failures. They started earlier, at
https://ci.chromium.org/p/v8/builders/ci/V8%20Win32/29444

Original change's description:
> [code] Separate instruction and metadata areas
>
> In this CL, Code object layout changes s.t. the instruction
> area is distinct / non-overlapping from the metadata area.
>
> On-heap Code objects now have a variable-size `body` area,
> containing distinct-but-adjacent `instruction` and `metadata`
> areas.
>
> Off-heap code (= embedded builtins) currently have the same,
> but in the future the metadata area will move elsewhere and
> no longer be adjacent to instructions.
>
> To implement this, the main changes are:
>
>  - The Code object header now contains instruction and metadata
>    sizes, and no longer contains the safepoint table offset
>    (it's implicitly the first table of the metadata section).
>  - The embedded metadata table contains information about both
>    instruction and metadata areas.
>
> I've also added assertions in spots that currently rely on a
> contiguous body area.
>
> Bug: v8:11036
> Change-Id: I940f0c70c07ad511dafd2d2c3e337de8c92cd4b9
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2491025
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70743}

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Tbr: leszeks@chromium.org, clemensb@chromium.org, dinfuehr@chromium.org
Bug: v8:11036
Change-Id: I238562d7e25cf28cc689856ee8b17f25627aaee7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2497162
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70747}