Vulkan does not have nested queries, so this was overbuilt. Get rid of
all the list wrangling and just have a single slot in the draw call for
the active occlusion query.

Bug: b/129706526
Change-Id: I30158895e6ef4edefd6e1de85766fb6c88bb528f
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/34728
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>