[backport#16078] replace tx hash with txid in test rawtransaction

Summary:
Comment by @sipa:

txid is correct here, as it's about arguments to the gettransansaction RPC.

This is a partial backport of Core PR16078
Commit https://github.com/bitcoin/bitcoin/pull/16078/commits/a65dafa8f12b3776328ace5cef24cb3fd126cfb1

The next commit is not needed as its changes are overwritten in D8027 / PR16251

See D1556 for why we have additional lines changed.

Test Plan: ninja && ninja && test/functional/test_runner.py rpc_rawtransaction.py

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, deadalnix

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D8050