* Require only 3 out of 5 signatures for old InstantSend in regtest mode
* Use LLMQs of size 5 with threshold of 3 for regtest
* Fix wrong check for out-of-range bits in CFixedBitSet
* Reduce number of masternodes in masternode/LLMQ tests
* Add missing \n to LogPrintf call
* Use correct indexes for isolated/receiver/sender nodes
The way it was before resulted in nodes 1-3 being unused and 6-8 being used
for these 3 special nodes even though these are masternodes.
* Avoid stopping/starting isolated node in p2p-instantsend.py
It's enough to disable networking for this node.
These tend to fail quite often on Travis due to multiple reasons. One
reason is that establishing intra quorum connections take some time and
the tests in dip3-deterministicmns.py did not sleep long enough. Another
reason is that the individual stages were not really checked for completion
but instead just a hardcoded sleep was used. And another reason was that
with a total of 13 MNs, it's not guaranteed that every DKG results in one
MN to be punished.
