Reland "Remove three flaky suppressions on Mac NVIDIA WebGL"

This reverts commit 46b1cc8c.

Reason for revert: was not the cause of the flaky crashes. See anglebug,com/2273 .

Original change's description:
> Revert "Remove three flaky suppressions on Mac NVIDIA WebGL"
> 
> This reverts commit 2a085af2.
> 
> Reason for revert: 5 GPU FYI bots started failing after this (extremely mysteriously, because this shouldn't affect them this way)
> https://ci.chromium.org/p/chromium/builders/ci/Mac%20FYI%20dEQP%20Release%20Intel/98243
> https://ci.chromium.org/p/chromium/builders/ci/Mac%20FYI%20Release%20%28Intel%29/19387
> https://ci.chromium.org/p/chromium/builders/ci/Mac%20FYI%20dEQP%20Release%20AMD/96734
> https://ci.chromium.org/p/chromium/builders/ci/Mac%20FYI%20Retina%20Release%20%28AMD%29/20055
> https://ci.chromium.org/p/chromium/builders/ci/Mac%20FYI%20GPU%20ASAN%20Release/14113
> 
> Original change's description:
> > Remove three flaky suppressions on Mac NVIDIA WebGL
> > 
> > These tests are no longer flaky
> >  conformance/ogles/GL/exp2/exp2_001_to_008.html (WebGL 1 and 2)
> >  conformance2/textures/canvas/tex-3d-rg16f-rg-float.html
> > 
> > Bug: 923080
> > Change-Id: Ibc0e4b488779a0843a787acacac6c9544e34c50f
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2029260
> > Auto-Submit: Austin Eng <enga@chromium.org>
> > Commit-Queue: Kenneth Russell <kbr@chromium.org>
> > Reviewed-by: Kenneth Russell <kbr@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#737052}
> 
> TBR=kbr@chromium.org,enga@chromium.org
> 
> Change-Id: I92cc1297bd71bc82b8e22662e58affe53b40ad6c
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 923080
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2033626
> Reviewed-by: ccameron <ccameron@chromium.org>
> Commit-Queue: ccameron <ccameron@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#737412}

TBR=ccameron@chromium.org,kbr@chromium.org,enga@chromium.org

Change-Id: Ib9d24c670f4f4d91f78e7b3696d571d4dcab1201
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 923080
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2033914Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#737530}

content/test/gpu/gpu_tests/test_expectations/webgl2_conformance_expectations.txt

@@ -332,7 +332,6 @@ crbug.com/483282 [ mac nvidia-0xfe9 ] deqp/functional/gles3/framebufferblit/defa
 crbug.com/483282 [ mac nvidia-0xfe9 ] conformance/attribs/gl-disabled-vertex-attrib.html [ Failure ]
 crbug.com/483282 [ mac nvidia-0xfe9 ] conformance/extensions/webgl-compressed-texture-size-limit.html [ RetryOnFailure ]
 crbug.com/996344 [ mac nvidia-0xfe9 ] conformance/glsl/bugs/vector-scalar-arithmetic-inside-loop.html [ Failure ]
-crbug.com/923080 [ mac nvidia-0xfe9 ] conformance/ogles/GL/exp2/exp2_001_to_008.html [ RetryOnFailure ]
 crbug.com/483282 [ mac nvidia-0xfe9 ] conformance/programs/gl-bind-attrib-location-long-names-test.html [ Failure ]
 crbug.com/483282 [ mac nvidia-0xfe9 ] conformance/programs/gl-bind-attrib-location-test.html [ Failure ]
 crbug.com/483282 [ mac nvidia-0xfe9 no-passthrough ] conformance2/glsl3/loops-with-side-effects.html [ Failure ]
@@ -341,7 +340,6 @@ crbug.com/996344 [ mac nvidia-0xfe9 ] conformance2/textures/misc/tex-base-level-
 crbug.com/483282 [ no-angle mac nvidia-0xfe9 ] conformance2/textures/misc/tex-input-validation.html [ Failure ]
 crbug.com/996344 [ mac nvidia-0xfe9 no-passthrough ] conformance2/textures/misc/tex-mipmap-levels.html [ Failure ]
 crbug.com/682834 [ mac nvidia-0xfe9 ] conformance2/textures/image_bitmap_from_video/tex-2d-rgba16f-rgba-half_float.html [ RetryOnFailure ]
-crbug.com/922517 [ mac nvidia-0xfe9 ] conformance2/textures/canvas/tex-3d-rg16f-rg-float.html [ RetryOnFailure ]
 crbug.com/784817 [ mac nvidia-0xfe9 ] conformance/glsl/bugs/init-array-with-loop.html [ Failure ]
 crbug.com/716652 [ sierra nvidia-0xfe9 ] deqp/functional/gles3/draw/random.html [ Failure ]
 crbug.com/483282 [ mac nvidia-0xfe9 ] deqp/functional/gles3/framebufferblit/conversion_04.html [ Failure ]

content/test/gpu/gpu_tests/test_expectations/webgl_conformance_expectations.txt

@@ -317,7 +317,6 @@ crbug.com/782317 [ mac intel ] conformance/rendering/rendering-stencil-large-vie
 # Mac Retina NVidia failures
 crbug.com/635081 [ mac nvidia-0xfe9 ] conformance/attribs/gl-disabled-vertex-attrib.html [ Failure ]
 crbug.com/996344 [ mac nvidia-0xfe9 ] conformance/glsl/bugs/vector-scalar-arithmetic-inside-loop.html [ Failure ]
-crbug.com/923080 [ mac nvidia-0xfe9 ] conformance/ogles/GL/exp2/exp2_001_to_008.html [ RetryOnFailure ]
 crbug.com/635081 [ mac nvidia-0xfe9 ] conformance/programs/gl-bind-attrib-location-long-names-test.html [ Failure ]
 crbug.com/635081 [ mac nvidia-0xfe9 ] conformance/programs/gl-bind-attrib-location-test.html [ Failure ]
 crbug.com/992313 [ mac nvidia-0xfe9 ] conformance/rendering/rendering-stencil-large-viewport.html [ RetryOnFailure ]