Any test that runs $listMqlEntities in the 'with-extensions' Evergreen variant includes all loaded extensions in its output. This is problematic for these tests because $listMqlEntities is a test stage that is used to confirm that all DocumentSources have been tested for certain conditions (e.g. all tests have been verified to work with null byte input - null_chars_string_input.js)

These tests generally end with an assertion like:
"Assert that every stage returned by $listMqlEntities is a) tested or b) explicitly skipped"

We ban these tests from running in 'with-extensions' because loaded extensions cause this assertion to fail. It would be ideal if we could add a "or c) is an extension stage".

SERVER-109838 is one possible solution to this issue, but it requires more overhead. SERVER-118820 added `LiteParsedDocumentSource::isRegisteredExtensionStage()` which could also be useful. We should investigate a final solution to this issue.