Issue #2262147 by sun: Various base test classes are not abstract.

...dules/locale/lib/Drupal/locale/Tests/LocaleUpdateBase.php

...ules/menu_ui/lib/Drupal/menu_ui/Tests/MenuWebTestBase.php

...ules/migrate/lib/Drupal/migrate/Tests/MigrateTestBase.php

...lib/Drupal/migrate_drupal/Tests/MigrateDrupalTestBase.php

...ib/Drupal/migrate_drupal/Tests/d6/MigrateNodeTestBase.php

...rupal/migrate_drupal/Tests/d6/MigrateTermNodeTestBase.php

.../lib/Drupal/migrate_drupal/Tests/d6/MigrateUploadBase.php

...lib/Drupal/options/Tests/OptionsDynamicValuesTestBase.php

...upal/options/Tests/OptionsDynamicValuesValidationTest.php

...ons/lib/Drupal/options/Tests/OptionsFieldUnitTestBase.php

...b/Drupal/options/Tests/OptionsSelectDynamicValuesTest.php

...uickedit/lib/Drupal/quickedit/Tests/QuickEditTestBase.php

...ystem/lib/Drupal/system/Tests/Module/ModuleEnableTest.php

.../system/lib/Drupal/system/Tests/Path/PathUnitTestBase.php

...rupal/system/Tests/Plugin/Discovery/DiscoveryTestBase.php

...b/Drupal/system/Tests/System/TokenReplaceUnitTestBase.php

core/modules/tour/lib/Drupal/tour/Tests/TourTestBase.php