layers: GH2145, fix comp<->uncomp copy val errors
layers: GH2145, fix comp<->uncomp copy val errors

For image-to-image copies, there are special cases for copies between
compressed and uncompressed images. These modifications to copy
extents are now allowed for in the validation checks.

Change-Id: I5d72e4ec621a6769a9a89e24aade5defa9ecabda

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools