sketchy integer casting in circuit_build_times_shuffle_and_store_array

In circuit_build_times_parse_state() we have

  uint32_t loaded_cnt

which we increment as we read each line. Then we

  circuit_build_times_shuffle_and_store_array(cbt, loaded_times, loaded_cnt);

and circuit_build_times_shuffle_and_store_array() receives its third argument as "int num_times".

I don't think there are actual problems here (yet), because we have several checks, like

  if (loaded_cnt != state->TotalBuildTimes) {

But handing a uint32_t into an int should be avoided.

Reported by doors.