Revert of Roll WebGL conformance tests. (patchset #4 id:250001 of https://codereview...

Revert of Roll WebGL conformance tests. (patchset #4 id:250001 of https://codereview.chromium.org/641173002/)

Reason for revert:
might cause a bunch of texture related tests to timeout

conformance_textures_texture_formats_test
conformance_textures_texture_hd_dpi
conformance_textures_texture_mips
conformance_textures_texture_npot
conformance_textures_texture_npot_video
conformance_textures_texture_size
conformance_textures_texture_size_cube_maps
conformance_textures_texture_size_limit
conformance_textures_texture_sub_image_cube_maps
conformance_textures_texture_transparent_pixels_initialized
conformance_textures_texture_upload_cube_maps

Original issue's description:
> Roll WebGL conformance tests.
>
> BUG=401311,421705
> TEST=gpu bots
> NOTRY=true
> R=kbr@chromium.org
>
> Committed: https://crrev.com/84d03b89afa3baade276d0f7ac7892ab77ed8d21
> Cr-Commit-Position: refs/heads/master@{#299134}

TBR=kbr@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=401311,421705

Review URL: https://codereview.chromium.org/648833003

Cr-Commit-Position: refs/heads/master@{#299166}