Cleanup & Fix Simulator Sub Epoch Logic

[jack60612]

Purpose:

This fixes an issue where a sub epoch might not be included if the simulator decides to overflow blocks, as it checks if there is a difficulty change, and therefore a new epoch instead of a sub epoch

Current Behavior:

No Breaking Change

New Behavior:

N/A

Testing Notes:

Testing is borderline impossible, because it requires making hundreds of thousands of blocks, however @nirajpathak13 said the issue was fixed.

Crash log before fix:

(venv) niraj@summer:~/development/chia/chia-blockchain$ Traceback (most recent call last):
  File "/home/niraj/development/chia/chia-blockchain/venv/bin/chia_full_node", line 8, in <module>
    sys.exit(main())
  File "/home/niraj/development/chia/chia-blockchain/chia/server/start_full_node.py", line 117, in main
    return async_run(coro=async_main(service_config), connection_limit=target_peer_count)
  File "/home/niraj/development/chia/chia-blockchain/chia/server/start_service.py", line 319, in async_run
    return asyncio.run(coro)
  File "/usr/lib/python3.8/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/usr/lib/python3.8/asyncio/base_events.py", line 616, in run_until_complete
    return future.result()
  File "/home/niraj/development/chia/chia-blockchain/chia/server/start_full_node.py", line 100, in async_main
    await service.run()
  File "/home/niraj/development/chia/chia-blockchain/chia/server/start_service.py", line 224, in run
    await self.start()
  File "/home/niraj/development/chia/chia-blockchain/chia/server/start_service.py", line 183, in start
    await self._node._start()
  File "/home/niraj/development/chia/chia-blockchain/chia/full_node/full_node.py", line 401, in _start
    await self.peak_post_processing_2(full_peak, None, state_change_summary, ppp_result)
  File "/home/niraj/development/chia/chia-blockchain/chia/full_node/full_node.py", line 1522, in peak_post_processing_2
    await self.send_peak_to_timelords(block)
  File "/home/niraj/development/chia/chia-blockchain/chia/full_node/full_node.py", line 731, in send_peak_to_timelords
    ses: Optional[SubEpochSummary] = next_sub_epoch_summary(
  File "/home/niraj/development/chia/chia-blockchain/chia/consensus/make_sub_epoch_summary.py", line 198, in next_sub_epoch_summary
    return make_sub_epoch_summary(
  File "/home/niraj/development/chia/chia-blockchain/chia/consensus/make_sub_epoch_summary.py", line 68, in make_sub_epoch_summary
    uint8(curr.height % constants.SUB_EPOCH_BLOCKS),
  File "/home/niraj/development/chia/chia-blockchain/chia/util/struct_stream.py", line 73, in __init__
    raise ValueError(f"Value {self} does not fit into {type(self).__name__}")
ValueError: Value 335 does not fit into uint8

[arvidn]

it looks correct, but I'm not very familiar with this code. I think leaving some comments explaining why the previous code was wrong (perhaps by explaining why the new code is correct) would be helpful