tests: Add fuzzing harness for various CTx{In,Out} related functions

Summary:
Backport of core PR17093.

The missing corpora change is not necessary for us.

Test Plan:

ninja bitcoin-fuzzers
./test/fuzz/test_runner.py <path_to_corpus>

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D8140