Issue #3270461 by marcusml: Tests $modules property should be declared protected

modules/demo/tests/src/Functional/TMGMTDemoTest.php

...c/Functional/ContentEntitySourceContentModerationTest.php

.../Functional/ContentEntitySourceTranslatableEntityTest.php

...tests/src/Functional/ContentTmgmtEntitySourceListTest.php

...unctional/ContentTmgmtEntitySourceNoCanonicalLinkTest.php

...t/tests/src/Functional/ContentTmgmtEntitySourceUiTest.php

sources/content/tests/src/Kernel/ContentEntityLinkTest.php

...ces/content/tests/src/Kernel/ContentEntityMetatagTest.php

sources/content/tests/src/Kernel/ContentEntityPathTest.php

...s/src/Kernel/ContentEntitySourceContentModerationTest.php

.../content/tests/src/Kernel/ContentEntitySourceUnitTest.php

...rnel/ContentEntitySourceUntranslatableTargetsUnitTest.php

...content/tests/src/Kernel/ContentEntitySuggestionsTest.php

sources/content/tests/src/Kernel/ContentEntityTestBase.php

...ent/tests/src/Kernel/ContentEntityUpdateParagraphTest.php

sources/locale/tests/src/Functional/LocaleSourceUiTest.php

sources/locale/tests/src/Kernel/LocaleSourceTest.php

...mgmt_config/tests/src/Functional/ConfigSourceListTest.php

.../tmgmt_config/tests/src/Functional/ConfigSourceUiTest.php

...es/tmgmt_config/tests/src/Kernel/ConfigSourceUnitTest.php