Issue #3260227 by mondrake: Move driver specific database Unit tests to their modules

(cherry picked from commit f4b955cf)

core/tests/Drupal/Tests/Core/Database/Driver/mysql/ConnectionTest.php → core/modules/mysql/tests/src/Unit/ConnectionTest.php

 <?php
 
-namespace Drupal\Tests\Core\Database\Driver\mysql;
+namespace Drupal\Tests\mysql\Unit;
 
 use Drupal\mysql\Driver\Database\mysql\Connection;
 use Drupal\Tests\UnitTestCase;

core/tests/Drupal/Tests/Core/Database/Driver/mysql/install/TasksTest.php → core/modules/mysql/tests/src/Unit/InstallTasksTest.php

 <?php
 
-namespace Drupal\Tests\Core\Database\Driver\mysql\install;
+namespace Drupal\Tests\mysql\Unit;
 
 use Drupal\mysql\Driver\Database\mysql\Connection;
 use Drupal\mysql\Driver\Database\mysql\Install\Tasks;
@@ -12,7 +12,7 @@
  * @coversDefaultClass \Drupal\mysql\Driver\Database\mysql\Install\Tasks
  * @group Database
  */
-class TasksTest extends UnitTestCase {
+class InstallTasksTest extends UnitTestCase {
 
   /**
    * A connection object prophecy.

core/tests/Drupal/Tests/Core/Database/Driver/pgsql/PostgresqlSchemaTest.php → core/modules/pgsql/tests/src/Unit/SchemaTest.php

 <?php
 
-namespace Drupal\Tests\Core\Database\Driver\pgsql;
+namespace Drupal\Tests\pgsql\Unit;
 
 use Drupal\pgsql\Driver\Database\pgsql\Schema;
 use Drupal\Tests\UnitTestCase;
@@ -11,7 +11,7 @@
  * @coversDefaultClass \Drupal\pgsql\Driver\Database\pgsql\Schema
  * @group Database
  */
-class PostgresqlSchemaTest extends UnitTestCase {
+class SchemaTest extends UnitTestCase {
 
   /**
    * The PostgreSql DB connection.

core/tests/Drupal/Tests/Core/Database/Driver/sqlite/ConnectionTest.php → core/modules/sqlite/tests/src/Unit/ConnectionTest.php

 <?php
 
-namespace Drupal\Tests\Core\Database\Driver\sqlite;
+namespace Drupal\Tests\sqlite\Unit;
 
 use Drupal\sqlite\Driver\Database\sqlite\Connection;
 use Drupal\Tests\Core\Database\Stub\StubPDO;