This reverts commit 27d3c939.

Reason for revert: Investigation is unable to reproduce the regresion.
Shows up on the perf CI.

Original change's description:
> Revert "Vulkan: Accelerate Texture PBO updates"
> 
> This reverts commit efb45eda.
> 
> Reason for revert: Significant perf regression on several benchmarks.
> See bug for more details.
> 
> Bug: chromium:1027098
> 
> Original change's description:
> > Vulkan: Accelerate Texture PBO updates
> > 
> > If the format of the image and the PBO match,
> > use a vkCmdCopyBufferToImage transfer operation.
> > 
> > Test: angle_end2end_tests --gtest_filter=*PBOCompressedSubImage*
> >       angle_end2end_tests --gtest_filter=*PBOWithMultipleDraws*
> >       dEQP-GLES3.functional.texture.specification.tex*image*d_pbo*
> > Bug: angleproject:3777
> > Change-Id: I3f271024a635be113202a16f8893a199c194172d
> > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1906203
> > Reviewed-by: Cody Northrop <cnorthrop@google.com>
> > Commit-Queue: Mohan Maiya <m.maiya@samsung.com>
> 
> TBR=cnorthrop@google.com,syoussefi@chromium.org,jmadill@chromium.org,m.maiya@samsung.com,b.schade@samsung.com
> 
> # Not skipping CQ checks because original CL landed > 1 day ago.
> 
> Bug: angleproject:3777
> Change-Id: I774655962e9ab5a866b9324002fb8edae8550834
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1939927
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Commit-Queue: Jamie Madill <jmadill@chromium.org>

TBR=cnorthrop@google.com,syoussefi@chromium.org,jmadill@chromium.org,m.maiya@samsung.com,b.schade@samsung.com

Change-Id: I8560a2e70de230eac3256a1df5eb2ecaa6f26bcf
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1027098, angleproject:3777
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1939852Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>