turnip: fix dstBuffer coherence before copying queries
What does this MR do and why?
There can be other writes to the dstBuffer gated by proper barriers beforehand. e.g.
vkBeginCommandBuffer
vkCmdResetQueryPool
vkCmdFillBuffer -> fill dstBuffer to all zero
vkCmdPipelineBarrier -> barrier for dstBuffer
vkCmdWriteTimestamp
vkCmdCopyQueryPoolResults
vkCmdPipelineBarrier
vkEndCommandBuffer
Filed follow up cts issue: https://gitlab.khronos.org/Tracker/vk-gl-cts/-/issues/4567
TEST=dEQP-VK.pipeline.*.timestamp.*
with Venus
on Turnip
Fixes: 487aa807 ("tu: Rewrite flushing to use barriers")
To be noted: this fix is independent from !6320 (merged) (which no longer matters after turnip uses global bo list)