Issue #2680105 by Berdir: Convert database kernel tests to phpunit

...modules/system/src/Tests/Database/DatabaseWebTestBase.php

core/tests/Drupal/KernelTests/Core/Database/AlterTest.php

...ests/Drupal/KernelTests/Core/Database/BasicSyntaxTest.php

.../Drupal/KernelTests/Core/Database/CaseSensitivityTest.php

...tests/Drupal/KernelTests/Core/Database/ConnectionTest.php

...s/Drupal/KernelTests/Core/Database/ConnectionUnitTest.php

...ernelTests/Core/Database/DatabaseExceptionWrapperTest.php

...sts/Drupal/KernelTests/Core/Database/DatabaseTestBase.php

...s/Drupal/KernelTests/Core/Database/DeleteTruncateTest.php

core/tests/Drupal/KernelTests/Core/Database/FetchTest.php

...s/Drupal/KernelTests/Core/Database/InsertDefaultsTest.php

.../tests/Drupal/KernelTests/Core/Database/InsertLobTest.php

core/tests/Drupal/KernelTests/Core/Database/InsertTest.php

...ests/Drupal/KernelTests/Core/Database/InvalidDataTest.php

...tests/Drupal/KernelTests/Core/Database/LargeQueryTest.php

core/tests/Drupal/KernelTests/Core/Database/LoggingTest.php

core/tests/Drupal/KernelTests/Core/Database/MergeTest.php

core/tests/Drupal/KernelTests/Core/Database/NextIdTest.php

core/tests/Drupal/KernelTests/Core/Database/QueryTest.php

...tests/Drupal/KernelTests/Core/Database/RangeQueryTest.php