PhpUnitApiFindAllClassFilesTest still not finding all namespace errors

Problem/Motivation

#3612498: PhpUnitApiFindAllClassFilesTest not finding namespace errors addressed some incorrect test file namespaces that PhpUnitApiFindAllClassFilesTest.php failed on 11.x but not main.

#3571580-54: add a generic bundle type entity delete form shows that the fix was not comprehensive, maybe because the test was in core not a module namespace?

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet