llvmpipe/draw: generated primitives query has d3d semantics, not gallium/GL semantics
The gallium docs say:
"PIPE_QUERY_PRIMITIVES_GENERATED
returns a 64-bit integer indicating
the number of primitives processed by the pipeline (regardless of whether
stream output is active or not)."
which is the GL interpretation for that query.
However draw implements the D3D semantics which means prim gen is only meaningful is streamout is active.