This reverts commit e3c35736.

Reason for revert: Fixed parent CL

Original change's description:
> Revert "Vulkan: Generate gl_Position.z correction in SPIR-V"
>
> This reverts commit 1e4f8b02.
>
> Reason for revert:
> Earlier CL breaks pre-rotation:
> https://chromium-review.googlesource.com/c/angle/angle/+/2598584
>
> Original change's description:
> > Vulkan: Generate gl_Position.z correction in SPIR-V
> >
> > Instead of having the translator output code to transform gl_Position.z
> > to Vulkan clip space in the vertex stage, this change makes the SPIR-V
> > transformer perform this operation on the last geometry stage.
> >
> > An alternative solution would be to generate this transformation in the
> > translator in every geometry stage, each controlled by a separate
> > specialization constant.  This change avoids unnecessary modifications
> > to earlier stages.  Additionally, the transformer is already modifying
> > gl_Position.xy for pre-rotation, so the addition of a small
> > transformation of gl_Position.z in the same spot is rather trivial.
> >
> > Bug: angleproject:5479
> > Change-Id: Id971179ba47b206204bfdaf3b2b295ef97dd5117
> > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2598585
> > Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
> > Reviewed-by: Charlie Lao <cclao@google.com>
> > Reviewed-by: Jamie Madill <jmadill@chromium.org>
>
> TBR=syoussefi@chromium.org,jmadill@chromium.org,cclao@google.com
>
> Change-Id: I3bdf3d6f743125eaf552608f2664b715bd6935c5
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: angleproject:5479
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2634203
> Reviewed-by: Tim Van Patten <timvp@google.com>
> Commit-Queue: Tim Van Patten <timvp@google.com>

TBR=timvp@google.com,syoussefi@chromium.org,jmadill@chromium.org,cclao@google.com

# Not skipping CQ checks because this is a reland.

Bug: angleproject:5479
Change-Id: Id23052b8fc6bffa5bab20cb93eb21ea49a0f80d7
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2633710
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>