Use hasData/hasUndo instead of masking with BLOCK_HAVE_DATA/BLOCK_HAVE_UNDO

Summary:
As per title.

Depends on D1450

Test Plan:

make check

Reviewers: #bitcoin_abc, schancel

Reviewed By: #bitcoin_abc, schancel

Subscribers: schancel, teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1451