We assume the pixels of an image can be addressed with a signed 32-bit
offset, including any padding. For a 3D image it's possible to exceed
this without exceeding the per-dimension limits. Lowering the per-
dimension limit so the allocation is always less than 2 GiB makes them
unreasonably small, so instead we must check the total size.

Use 1 GiB as the soft limit in OpenGL.

Bug chromium:835299

Change-Id: I9c5184002c1710e3923b549f8c21e7f6a516e1c7
Reviewed-on: https://swiftshader-review.googlesource.com/18869Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>