This reverts commit 499173de.

Reason for revert: Causes unexpected HLSL compiler errors in some
cases. See bug.

Bug: angleproject:5094

Original change's description:
> Pass #pragma optimize setting down to compilation.
>
> This will allow us to disable optimizations in the back-end. This can
> be useful both for developers and for ANGLE to disable very slow
> shader compilation on D3D11.
>
> Also apply this pragma to VerifyMaxVertexUniformVectorsWithSamplers.
> Reduces compilation time by half in local testing.
>
> Bug: angleproject:5076
> Change-Id: I64ad576e11b9cee5b41f8af0d3621570304d65c2
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2420749
> Commit-Queue: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
> Reviewed-by: Geoff Lang <geofflang@chromium.org>

TBR=geofflang@chromium.org,jonahr@google.com,jmadill@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: angleproject:5076
Change-Id: I733e788fe8e9421ae0af662c0eb51af1ed79dde3
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2429517Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>