[bf4]

Extracted from #1497.

This PR contains the two test and CI fixes from that PR, without its Rails 8.1 routing implementation change:

• Load Ruby's logger before Rails test dependencies so the Rails 6.0 and 6.1 matrix jobs can boot with the currently resolved gems.
• Add the routing regression tests with path assertions based on the configured route formatter. The formatter fix in fix: backport Rails 8.1 routing keywords to release-0-9 #1497 edits a test file introduced there, so the complete corrected test file is included here.

Validation: rake test TEST=test/unit/routing_compatibility_test.rb passes locally (2 runs, 0 failures), and git diff --check is clean.

[bf4]

xref #1496