This reverts commit 8d51d561.

Reason for revert: This has runtime failures because including
cmx fragments isn't working ocrrectly. Still investigating why
this wasn't discovered by CQ.

Original change's description:
> [fuchsia] Use SDK provided gn templates for v8_unittests
>
> cr_fuchsia_package is deprecated in favor of using the Fuchsia
> SDK provided rules directly.
>
> Bug: chromium:1092804
> Change-Id: I86a59b6a717cb0aa8c3473e8410bdd98f0ffd042
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3537883
> Reviewed-by: Victor Gomes <victorgomes@chromium.org>
> Reviewed-by: Wez <wez@chromium.org>
> Reviewed-by: Camillo Bruni <cbruni@chromium.org>
> Commit-Queue: Bryant Chandler <bryantchandler@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#79763}

Bug: chromium:1092804
Change-Id: I33e8a6f07c99d7040cffa579a95508e79904889e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3572005
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79796}