If the proof no longer exists in the peer manager, then it has been evicted from both the pools and is no longer worth polling.

The addProofToReconcile() now returns a bool and the tests are updated accordingly. Cleaning up the actual queries to remove evicted proofs will be done in another diff.

Note to reviewers: I did make another IsWorthPolling function because:

1. This would be a single line method, so very few to gain
2. This needs access to the processors private members peer manager and its lock so needs to be a private method. For the blocks this is a static function so this creates confusion.

Ret T1854.