Find a proper way to manage including/excluding database-driver-specific tests

Problem/Motivation

Lastly discussed from #3098426-10: EntityQueryTest::testToString fails with non-core db drivers onwards, but really popped up several times already,

+    if (!in_array(Database::getConnection()->driver(), ['mysql', 'sqlite', 'pgsql'])) {
+      $this->markTestSkipped("This test only runs for Drupal core database drivers");
+    }

feels fragile.

We should have a more structured way to include/exclude tests that are database specific in the test runs.

Proposed resolution

From @alexpott in #3098426-13: EntityQueryTest::testToString fails with non-core db drivers:

it involves tagging tests and test methods with additional @group so that we can agree what tests/methods need to be db agnostic and provide a good coverage for a contrib / custom db driver. Or we can go the other way... and add a group to tests we know are SQL database specific and then contrib / custom drivers can use --exclude-group.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet