diff --git a/core/modules/simpletest/tests/fixtures/simpletest_phpunit_run_command_test.php b/core/modules/simpletest/tests/fixtures/simpletest_phpunit_run_command_test.php
deleted file mode 100644
index 2a01d30..0000000
--- a/core/modules/simpletest/tests/fixtures/simpletest_phpunit_run_command_test.php
+++ /dev/null
@@ -1,26 +0,0 @@
-<?php
-
-namespace Drupal\Tests\simpletest\Unit;
-
-use Drupal\Tests\UnitTestCase;
-
-/**
- * This test crashes PHP.
- *
- * To avoid accidentally running, it is not in a normal PSR-4 directory, the
- * file name does not adhere to PSR-4 and an environment variable also needs to
- * be set for the crash to happen.
- *
- * @runTestsInSeparateProcesses
- * @preserveGlobalState disabled
- */
-class SimpletestPhpunitRunCommandTestWillDie extends UnitTestCase {
-
-  public function testWillDie() {
-    if (getenv('SimpletestPhpunitRunCommandTestWillDie') === 'fail') {
-      // This causes a segmentation fault.
-      preg_match('/(.(?!b))*/', str_repeat("a", 10000));
-    }
-  }
-}
-
diff --git a/core/modules/simpletest/tests/src/Unit/SimpletestPhpunitRunCommandTest.php b/core/modules/simpletest/tests/src/Unit/SimpletestPhpunitRunCommandTest.php
deleted file mode 100644
index f49fe5f..0000000
--- a/core/modules/simpletest/tests/src/Unit/SimpletestPhpunitRunCommandTest.php
+++ /dev/null
@@ -1,43 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Tests\simpletest\Unit\SimpletestPhpunitRunCommandTest.
- */
-
-namespace Drupal\Tests\simpletest\Unit;
-
-use Drupal\Core\DependencyInjection\ContainerBuilder;
-use Drupal\Tests\UnitTestCase;
-
-/**
- * Tests simpletest_run_phpunit_tests() handles PHPunit fatals correctly.
- *
- * @group simpletest
- *
- * @runTestsInSeparateProcesses
- * @preserveGlobalState disabled
- */
-class SimpletestPhpunitRunCommandTest extends UnitTestCase {
-
-  function testSimpletestPhpUnitRunCommand() {
-    include_once __DIR__ .'/../../fixtures/simpletest_phpunit_run_command_test.php';
-    $app_root = __DIR__ . '/../../../../../..';
-    include_once "$app_root/core/modules/simpletest/simpletest.module";
-    include_once "$app_root/core/includes/file.inc";
-    $container = new ContainerBuilder;
-    $container->set('app.root', $app_root);
-    $file_system = $this->prophesize('Drupal\Core\File\FileSystemInterface');
-    $file_system->realpath('public://simpletest')->willReturn(sys_get_temp_dir());
-    $container->set('file_system', $file_system->reveal());
-    \Drupal::setContainer($container);
-    $test_id = basename(tempnam(sys_get_temp_dir(), 'xxx'));
-    foreach (['pass', 'fail'] as $status) {
-      putenv('SimpletestPhpunitRunCommandTestWillDie=' . $status);
-      $ret = simpletest_run_phpunit_tests($test_id, ['Drupal\Tests\simpletest\Unit\SimpletestPhpunitRunCommandTestWillDie']);
-      $this->assertSame($ret[0]['status'], $status);
-    }
-    unlink(simpletest_phpunit_xml_filepath($test_id));
-  }
-
-}