Function emit_wmma_cpasync_bench 

pub fn emit_wmma_cpasync_bench(
    kind: MmaKind,
    tile: &WmmaTile,
    stages: usize,
    m: usize,
    k: usize,
    n: usize,
) -> String

Timing bench for the cp.async double-buffered WMMA kernel at kind + tile + stages — prints GOPS.