Fix vertex count calculation in XFB query tests

Fix vertex count calculation in XFB query tests

The primitive to vertex count calculation for
VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY was
`(primCount + 4u) * 2u` when it should be `primCount * 2u + 4u`.

This change affects the bufferSize parameter passed to the tests.
The vertex count returned by this function is part of the test name
so the affected test cases are also renamed.

Affects:
dEQP-VK.transform_feedback.simple.query*
dEQP-VK.transform_feedback.simple.host_query_reset*

Components: Vulkan

VK-GL-CTS issue: 2934

Change-Id: I59e95a3240c6c45f8caf0dd4dc5b61c593059304