testing: Suppress logging exceptions when pytest captures output

[cdecker]

This PR fixes issues with the logging library raising exceptions when pytest swaps out sys.stdout/sys.stderr for output capture.

Changes

1. Added TEST_LOG_IGNORE_ERRORS environment variable to disable logging.raiseExceptions in the test setup fixture
2. Set TEST_LOG_IGNORE_ERRORS=1 in:
   • GitHub Actions CI workflow (.github/workflows/ci.yaml)
   • Coverage nightly workflow (.github/workflows/coverage-nightly.yaml)
   • Makefile test target
   • Taskfile.yml

Problem

The logging library was raising exceptions when pytest captured output by temporarily replacing sys.stdout/sys.stderr. This caused test failures due to logging handlers attempting to write to closed file descriptors.

Solution

When TEST_LOG_IGNORE_ERRORS=1 is set, the test fixture now disables logging.raiseExceptions, allowing tests to continue even if logging encounters errors during pytest's output capture.

[rustyrussell]

Uh. What problem are you seeing? This is an awful lot of weird LLM code that nobody understands to fix a problem I haven't seen described...

Edit: Ah, those files look like accidental adds! No wonder I was confused!!

[cdecker]

YEah, I need to clean this one up, since I was also testing if we can trace the test execution closer, learning where we lose time, but those scripts and shims are definitely premature in this PR.

[cdecker]

And just to add the missing context here: this is an attempt to prevent the flood of "operation on a closed file" tracebacks that have a tendency of polluting logs. The root cause is that the subprocesses continue emitting logs, but the logging sync has been closed by the output capturing sub-system in pytest, thus hiding the actual log lines, in a flood of tracebacks.