Function run_nanos 

pub fn run_nanos(
    stmts: &[Stmt<'_>],
    interner: &Interner,
    types: Option<&TypeRegistry>,
    iters: usize,
) -> Option<u128>

RUN-ONLY wall-time — the MIN nanoseconds over iters executions of the CHIP bytecode on the register VM, compiled ONCE (so parse / compile / stdlib-prelude load are excluded). This is the fair host counterpart to the FPGA soft-core’s on-chip cycle counter, which also measures execution only — and it runs the SAME compile_for_chip bytecode the silicon executes, so VM-vs-FPGA is one instruction stream, host CPU vs custom silicon. None if the program does not compile to the chip subset.