The moment of truth. Write check_both(src, expected):

1. Run the interpreter on src -> get the interpreter's answer
2. Run the compiler on src -> get WAT text
3. Run the VM on the WAT -> get the VM's answer
4. Compare both answers to expected

fn check_both(input: []const u8, expected: i64) void {
    // Interpret
    source = input;
    pos = 0;
    num_vars = 0;
    fn_count = 0;
    return_flag = false;
    save_depth = 0;
    skip();
    const interp: i64 = program();

    // Compile
    c_program(input);

    // Run VM
    const compiled: i64 = vm_run_wat(out[0..out_len]);

    if (interp == expected and compiled == expected) {
        print("  ok {d}\n", .{expected});
    } else {
        print("  FAIL interp={d} compiled={d} want={d}\n", .{ interp, compiled, expected });
    }
}