Kill OutputChecker, use assert_start_raises_init_error instead

Summary:
assert_start_raises_init_error was backported from core's PR9832

This diff also remove the old system used to check for error in the output that were added in various tests ( notably abc-cmdline.py ).

Test Plan:

make check
./test/functional/test_runner.py --extended

Reviewers: #bitcoin_abc, schancel

Reviewed By: #bitcoin_abc, schancel

Differential Revision: https://reviews.bitcoinabc.org/D981