PR11771 backport https://github.com/bitcoin/bitcoin/pull/11771/files
95e2e9a [tests] Change invalidtxrequest to use BitcoinTestFramework (John Newbery)
359d067 [tests] Fix flake8 warnings in invalidtxrequest (John Newbery)
c32cf9f [tests] Add P2PDataStore class (John Newbery)
cc046f6 [tests] Reduce NodeConn connection logging from info to debug (John Newbery)
Pull request description:
Next step in #10603 - first commit changes log level for an internal log from INFO to DEBUG. (Not really related, but I started finding the INFO level logging annoying when debuging test failures) - second commit introduces a `P2PStub` class - a subclass of `NodeConnCB` which has its own block and tx store and responds appropriately to getdata requests. Not all the functionality is used in `invalidtxrequest.py`, but will be used in `invalidblockrequest.py` and `p2p-fullblocktest` when those are changed to use `BitcoinTestFramework` - third commit tidies up `invalidtxrequest.py` - fourth commit removes usage of `ComparisonTestFramework`
Backport note: the "Invalid OP_IF construction" was changed to a pushonly failure.
Depends on D3501