Issue #1754244 by dawehner: Add a generic testcase for the field base.

lib/Drupal/views/Plugin/views/field/FieldPluginBase.php

lib/Drupal/views/Tests/Handler/FieldTest.php

...views_test_config/config/views.view.test_field_tokens.yml

tests/views_test_data/config/views.view.test_click_sort.yml

.../views_test_data/config/views.view.test_field_classes.yml

...s/views_test_data/config/views.view.test_field_output.yml

...b/Drupal/views_test_data/Plugin/views/field/FieldTest.php

tests/views_test_data/views_test_data.install

views.module