Revert "[storage-benchmarks] Add support for sorrel"

This reverts commit 35ab02313277284717e54739e9360acafe61f186.

Reason for revert: broke the tree

Original change's description:
> [storage-benchmarks] Add support for sorrel
>
> New partitions can't be created on sorrel but we can use the existing
> pad_rw partition.
>
> Blobs are deleted after each iteration otherwise the benchmark might run
> out of space in pad_rw.
>
> Bug: b/454946355
> Change-Id: Ic533901277ed3d6126d0688f64def1192c79e7cd
> Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1545042
> Reviewed-by: Martin Lindsay <mlindsay@google.com>
> Commit-Queue: Chris Drouillard <cdrllrd@google.com>

Bug: b/454946355
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: I19ec9edd474402ddcb7f66a3734e8a53262584ee
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1554264
Commit-Queue: Brian Bosak <bbosak@google.com>
Exempt: RubberStamper 🤖 <android-build-ayeaye@system.gserviceaccount.com>