Fix "mempool analyzer" tool

[gregorycoppola]

The "mempool analyzer tool", once advanced as #3020, but never checked in, is broken, in the sense that I can't get it to work on my node.

I'm not sure what is wrong.

We should consider:

1. fixing it
2. turning it into a process that runs continually

To be a process that runs continually, we could either:

1. make it like the "mock miner", but have it iterate over all transactions
2. just have this process each transaction once, queued up when it is received in the mempool, and removed from the queue once it has been tested a single time. This is different than the "mock miner" style set-up, where a transaction could be processed multiple times, giving more up-to-date information, but making it harder to get through all transactions.

[jcnelson]

Closing due to inactivity.

[blockstack-devops]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.