Split abc-p2p-fullblocktests so that the part about compact block is in its own test.

Summary:
As per title. It avoid to create a huge test that does everything. We'll get better feedback and it'll be easier to extend testing from there.

Depends on D1138

Test Plan:

./test/functional/test_runner.py abc-p2p-fullblocktest abc-p2p-compactblocks

Reviewers: #bitcoin_abc, schancel

Reviewed By: #bitcoin_abc, schancel

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1143