Issue #2822382 by voleger, pfrenssen, erozqba, jungle, RytoEX, borisson_, jofitz, shashikant_chauhan, sidharthap, dawehner, xjm, kiamlaluno, catch, daffie, klausi: Make every $modules property protected on classes extending BrowserTestBase and KernelTestBase (cherry picked from commit 6bf02d96)
