This reverts commit 703b0b31.

Reason for revert: a simpler approach will be used instead.

Original change's description:
> [ptr-compr-8gb] Align runtime allocations to 8 bytes
>
> In order to support a larger heap cage (8GB, 16GB), the cage offset
> will take up more than 32 bits. As a consequence, for 8GB cages, the
> least significant bit of the cage offset will overlap with the most
> significant bit of the tagged offset. To avoid this, allocations need
> to be aligned to 8 bytes to free up one bit from the offset.
> All changes are deactivated behind the build flag
> `v8_enable_pointer_compression_8gb`.
>
> Bug: v8:13070
> Change-Id: Ibb0bd0177f3e88dcd24fc0ee7526335df0faa987
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3791052
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Auto-Submit: Teo Dutu <teodutu@google.com>
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#82299}

Bug: v8:13070
Change-Id: I5cb60f8e4500c908bdef5d417393edbe89652c9c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3877146Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Auto-Submit: Teo Dutu <teodutu@google.com>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83030}