This reverts commit 76181384.

Reason for revert: Bug exposed by this is fixed in https://chromium-review.googlesource.com/c/angle/angle/+/2896168

Original change's description:
> Vulkan: Disable BufferVk suballocation
>
> There are still unresolved bugs.
>
> Bug: angleproject:5719
> Bug: chromium:1209197
> Change-Id: I6a971c421d0ae266404d1ecbf8741a9747a4e809
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2897545
> Reviewed-by: Cody Northrop <cnorthrop@google.com>
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
> Commit-Queue: Tim Van Patten <timvp@google.com>

Bug: angleproject:5719
Bug: chromium:1209197
Change-Id: I5c24b5f6476eab98ed5a7b90b3d1796ffc7ca106
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2896169
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>