tests: Add FramebufferIncompatible test
tests: Add FramebufferIncompatible test

Test where secondary command buffer has different framebuffer than
primary command buffer, which is a violation.
Update documentation.

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