Merge branch 'validation_fix_api_command_buffers' into 'vulkan-cts-1.0-dev'

dEQP-VK.api.command_buffers: remove bad test

I think two test cases were wrong -- they allocated zero command buffers which shouldn't be allowed. Layers treat it as an error and I filed a spec bug because it's not stated explicitly. I'm removing these two tests.

See #357 for details on validation task.

### Vulkan spec issue

- [Issue 292](https://gitlab.khronos.org/vulkan/vulkan/issues/292) - VkCommandBufferAllocateInfo valid usage

See merge request !525

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

diff --cc external/vulkancts/mustpass/1.0.0/vk-default.txt
Simple merge