Enable ASTC 3D textures.

ETC are still unsupported, since dEQP fails if we indicate support.

Bug: angleproject:3188
Test: dEQP.KHR_GLES2/texture_3d_compressed_texture_*astc*
Test: dEQP.KHR_GLES2/texture_3d_compressed_texture_negative_compressed_tex_image
Change-Id: I8559ae42d19e63fdf96ea7a49f2d7e3d5098771c
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1723094Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Tim Van Patten <timvp@google.com>