Test vkCmdBindVertexBuffers2EXT with size and offset

Test vkCmdBindVertexBuffers2EXT with size and offset

Test both the size and offset parameters in the new vertex binding
function are used properly.

The new tests create vertex buffers which have the proper vertex data in
the middle of them, with wrong data before and after them. If any
implementation were to read data out of the precise range, the new tests
should not pass.

New tests:
dEQP-VK.pipeline.extended_dynamic_state.*.stride_with_offset_and_padding

Affected tests:
dEQP-VK.pipeline.extended_dynamic_state.*

Components: Vulkan
VK-GL-CTS issue: 2646

Change-Id: I97f385934fcd41e19b2448a54e4f28f8a8a9c24c