[ActionMailer] Rename test/test_test to test/test_case_test
[ci skip] add line about text layout
Merge pull request #16752 from Shruti2791/shruti_workspace

[ci skip] add line about text layout
Merge pull request #16751 from seuros/rename

[ActionMailer] Rename test/test_test to test/test_case_test
Clean up grammar from #16752 [ci skip]