Remove legacy experimental:true and its deprecation and test-files

One nit, please restore comment as it was in https://git.drupalcode.org/project/drupal/-/commit/94230c5aa0582de0fe2e9...

@andypost: These long links are really meh, and I think you might have missed adding the specific line number(s) to it, but I _think_ you're referring to this one in : https://git.drupalcode.org/project/drupal/-/commit/94230c5aa0582de0fe2e9... in core/modules/system/tests/modules/theme_page_test/theme_page_test.module?

Yes, added suggestion to apply

Yes, added suggestion to apply

Thanks @andypost, suggestion applied.

Ready to go

Committed/pushed to 11.x and cherry-picked to 10.3.x, thanks!

Spokje → closed merge request !6856

Automatically closed - issue fixed for 2 weeks with no activity.