Merge #15946: Allow maintaining the blockfilterindex when using prune

84716b134e Add "index/blockfilterindex -> validation -> index/blockfilterindex" to expected circular dependencies (Jonas Schnelli)
ab3a0a2fb9 Add functional test for blockfilterindex in prune-mode (Jonas Schnelli)
c286a22f7b Add debug startup parameter -fastprune for more effective pruning tests (Jonas Schnelli)
5e112269c3 Avoid pruning below the blockfilterindex sync height (Jonas Schnelli)
00d57ff768 Avoid accessing nullpointer in BaseIndex::GetSummary() (Jonas Schnelli)
6abe9f5b11 Allow blockfilter in conjunction with prune (Jonas Schnelli)

Pull request description:

  Maintaining the blockfilterindexes in prune mode is possible and may lead to efficient p2p based rescans of wallets (restore backups, import/sweep keys) beyond the prune height (rescans not part of that PR).

  This PR allows running the blockfilterindex(es) in conjunction with pruning.
  * Bitcoind/Qt will shutdown during startup when missing block data has been detected ([re]enable `-blockfilterindex` when we already have pruned)
  * manual block pruning is disabled during blockfilterindex sync
  * auto-pruning is delayed during blockfilterindex sync

  ToDos:
  * [x] Functional tests

ACKs for top commit:
  fjahr:
    Code review ACK 84716b1
  ryanofsky:
    Code review ACK 84716b134e. Only changes since last review were suggested new FindFilesToPrune argument and test.
  benthecarman:
    tACK 84716b134e

Tree-SHA512: 91d832c6c562c463f7ec7655c08956385413a99a896640b9737bda0183607fac530435d03d87c3c0e70c61ccdfe73fe8f3639bc7d26d33ca7e60925ebb97d77a

test/functional/test_runner.py

@@ -289,6 +289,7 @@ BASE_SCRIPTS = [
     'feature_help.py',
     'feature_shutdown.py',
     'p2p_ibd_txrelay.py',
+    'feature_blockfilterindex_prune.py'
     # Don't append tests at the end to avoid merge conflicts
     # Put them in a random line within the section that fits their approximate run-time
 ]