Fix regression in getrawtransaction

Summary:
Fixes a regression from D2499 where confirmations, time, and blocktime are no longer present in getrawtransaction. Also add sanity checks to rpc_rawtransaction.py to ensure these verbose-only values are included in the future.

This fixes this issue reported on Github: https://github.com/Bitcoin-ABC/bitcoin-abc/issues/303

Test Plan:

ninja check
test_runner.py

Reviewers: deadalnix, Fabien, #bitcoin_abc

Reviewed By: deadalnix, #bitcoin_abc

Subscribers: teamcity, schancel

Differential Revision: https://reviews.bitcoinabc.org/D2546