Merge branch 'jekstrand_copy_and_bit_usage_flags' into 'master'

copy_and_blit: Fix image/buffer create-time usage flags

For buffers, it had both source and destination marked as DST.  For images,
it both uploads and downloads the images, so it needs both set.

Fixes #199

See merge request !309

diff --cc external/vulkancts/modules/vulkan/api/vktApiCopiesAndBlittingTests.cpp
Simple merge