reverted:
--- b/core/lib/Drupal/Core/Installer/Exception/ActiveConfigurationExistsException.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\Installer\Exception\ActiveConfigurationExistsException.
- */
-
-namespace Drupal\Core\Installer\Exception;
-
-use Drupal\Core\StringTranslation\TranslationInterface;
-
-/**
- * Exception thrown if Drupal is installed already.
- */
-class ActiveConfigurationExistsException extends AlreadyInstalledException {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function __construct(TranslationInterface $string_translation, $message = '') {
-    $this->stringTranslation = $string_translation;
-    parent::__construct($string_translation, $this->t('Active configuration already exists.'));
-  }
-
-}
reverted:
--- b/core/lib/Drupal/Core/Installer/Exception/DatabaseAlreadyPopulatedException.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\Installer\Exception\DatabaseAlreadyPopulatedException.
- */
-
-namespace Drupal\Core\Installer\Exception;
-
-use Drupal\Core\StringTranslation\TranslationInterface;
-
-/**
- * Exception thrown if Drupal is installed already.
- */
-class DatabaseAlreadyPopulatedException extends AlreadyInstalledException {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function __construct(TranslationInterface $string_translation, $message = '') {
-    $this->stringTranslation = $string_translation;
-    parent::__construct($string_translation, $this->t('Database is already populated.'));
-  }
-
-}
reverted:
--- b/core/lib/Drupal/Core/Installer/Exception/InstallationTasksCompletedException.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\Installer\Exception\InstallationTasksCompletedException.
- */
-
-namespace Drupal\Core\Installer\Exception;
-
-use Drupal\Core\StringTranslation\TranslationInterface;
-
-/**
- * Exception thrown if Drupal is installed already.
- */
-class InstallationTasksCompletedException extends AlreadyInstalledException {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function __construct(TranslationInterface $string_translation, $message = '') {
-    $this->stringTranslation = $string_translation;
-    parent::__construct($string_translation, $this->t('Installation tasks have already been completed.'));
-  }
-
-}
reverted:
--- b/core/lib/Drupal/Core/Installer/Exception/SettingsAlreadyExistsException.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\Installer\Exception\SettingsAlreadyExistsException.
- */
-
-namespace Drupal\Core\Installer\Exception;
-
-use Drupal\Core\StringTranslation\TranslationInterface;
-
-/**
- * Exception thrown if Drupal is installed already.
- */
-class SettingsAlreadyExistsException extends AlreadyInstalledException {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function __construct(TranslationInterface $string_translation, $message = '') {
-    $this->stringTranslation = $string_translation;
-    parent::__construct($string_translation, $this->t('Configured settings.php already exists.'));
-  }
-
-}