Function execute_compiled_program_external_metrics 

pub fn execute_compiled_program_external_metrics(
    compiled: &CompiledProgram,
    state: &mut State,
    operators: &Operators,
    hosts: &HostFunctions,
) -> Result<(i64, usize), RuntimeError>

Execute compiled program and return (checksum, len) when possible.

This is a benchmark/metrics helper that avoids building JSON arrays for the external typed-map fast path.