Revert "[Fuchsia] Add Fuchsia GPU builders to chromium.gpu"

This reverts commit 3f5e501624ef2b52beb0017a160c24c196f7549c.

Reason for revert: Should not have been submitted initially,
builders not healthy enough.

Original change's description:
> [Fuchsia] Add Fuchsia GPU builders to chromium.gpu
>
> Bug: 1432398
> Change-Id: Iae4f44eebe6678d94228df8faafa379af7e03c39
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4897257
> Reviewed-by: Zijie He <zijiehe@google.com>
> Auto-Submit: Chong Gu <chonggu@google.com>
> Commit-Queue: Zijie He <zijiehe@google.com>
> Cr-Commit-Position: refs/heads/main@{#1207268}

Bug: 1432398
Change-Id: Id1418f30fafe33502679bfc06f4d1eabbc5157a0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4923178
Reviewed-by: Zijie He <zijiehe@google.com>
Commit-Queue: Zijie He <zijiehe@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1207274}