* test: Fix “local variable 'e' is assigned to but never used”
flake8 F841 lints, as of flake8 3.6.0
* test: Adapt test framework for chains other than "regtest"
Co-Authored-By: Jorge Timón <jtimon@jtimon.cc>
* test: Avoid hardcoding the chain name in combine_logs
This is a backport of Core PR16509
The original PR contains a lot of formatting that was made obsolete by our process.