Improve visual test runner: consolidate setup, add constants, remove dead code (#46217)

Just some code cleanup to improve the tests - make them better exemplars
for future use.

Release Notes:

- N/A
f4aad4bb27Richard Feldman committed on 1/7/2026, 3:57:13 AM· committed by GitHubparent8f961a4
2 files changedLine totals unavailable