This is a reland of 4f9d7a94

Original change's description:
> [snapshot] Align internal snapshot data
>
> When the snapshot blob is not aligned properly, loading it can cause a
> crash on platforms such as arm.
>
> This was exposed by a SIGBUS/BUS_ADRALN crash on arm when accessing
> the blob_data symbol (declared as a byte array) through a reinterpret
> cast to uintptr_t in an internal snapshot build.
>
> Thanks to florian.dold@gmail.com for the initial patch.
>
> Bug: v8:9171
> Change-Id: I99b071dec3733416f2f01b58a770e30d8f2dcdf2
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1582402
> Commit-Queue: Dan Elphick <delphick@chromium.org>
> Auto-Submit: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Dan Elphick <delphick@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#61000}

Tbr: delphick@chromium.org
Bug: v8:9171
Change-Id: I36f53647ff5c45bcc512147f082fdd069723175d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1587377Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61062}