Revert "Implements more pack/unpack states. Pack: row length, skip rows, skip pixels. Unpack: image height, skip images, skip rows, skip pixels. Note that PBOs are not covered by this change."

Expectations still not correct. This removes suppressions for two
failing tests:

functional.texture.specification.teximage3d_depth_pbo.depth_component32f_2d_array
dEQP-GLES3.functional.texture.specification.teximage3d_depth_pbo.depth32f_stencil8_2d_array

BUG=angleproject:512
BUG=angleproject:1095

This reverts commit 72e7013e.

Change-Id: Id81b6e616e61535b8504890ce57591813e22af69
Reviewed-on: https://chromium-review.googlesource.com/305521Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>