This reverts commit 5a9ce8cf.

Issue #3437623 by alexpott, kim.pepper, sakthi_dev: \Drupal\file\Upload\FileUploadHandler::handleFileUpload() should alway check that the uploaded file is valid

Issue #540008 by kristiaanvandeneynde, Spokje, daffie, clayfreeman, alexpott, eelkeblok, michaelfavia, ianthomas_uk, zaporylie, johnwebdev, abhisekmazumdar, anmolgoyal74, greggles, quietone, shaal, catch, rivimey, AaronMcHale, Berdir, ndf, xjm, finne, Wim Leers, esolitos, heddn, webchick, Bojhan, andypost, efpapado, benjifisher, lauriii, Gábor Hojtsy, moshe weitzman, harings_rob: Add a container parameter that can remove the special behavior of UID#1

Issue #3402294 by mstrelan, quietone, dww, smustgrave: Fix strict type errors: Convert FormattableMarkup to strings (complex replacement) in core Kernel tests

Issue #3426506 by kim.pepper, smustgrave, mstrelan, alexpott: Create enums for File exists options and deprecate consts

Revert "Issue #3432882 by kim.pepper, Satane, andypost, alexpott, longwave: Removed deprecated code in File module (core/module/file)"

This reverts commit 08c0efdf.

Issue #3432882 by kim.pepper, Satane, andypost, alexpott, longwave: Removed deprecated code in File module (core/module/file)

Issue #3419394 by quietone, longwave, smustgrave: File mime type and other file related words in the dictionary

Issue #3245446 by Akhil Babu, guiu.rocafort.ferrer, dww, zrpnr, Kanchan Bhogade, smustgrave, larowlan, schillerm, alexpott: Video files using the FileVideoFormatter have a fixed dimension

Issue #3420802 by kim.pepper, bkline, larowlan: [regression] file_save_upload does not properly handle extensions

Issue #3292350 by O'Briat, KlemenDEV, hswong3i, smustgrave, quietone: Update the file size in file_validate_image_resolution after resizing

Issue #3385845 by shalini_jha, smustgrave: PrivateFileOnTranslatedEntityTest should use API to set up language

Issue #3309104 by Bhanu951, acbramley, mondrake, ravi.shankar, smustgrave, daffie, alexpott, quietone, mstrelan: Replace REQUEST_TIME in Functional and FunctionalJavascript tests

Issue #3411266 by kim.pepper, quietone, smustgrave: Convert file_icon_class() and file_icon_map() to a utlity class and deprecate

Issue #3401730 by kim.pepper, smustgrave, longwave: Add default autoconfigure to all *.services.yml and remove event_subscriber tags

Issue #3112284 by Spokje, Bhanu951, acbramley, mpdonadio, mondrake, quietone, adityasingh, andypost, JeroenT, vladbo, pifagor, daffie, voleger: Replace REQUEST_TIME in Kernel tests

Issue #3353210 by mondrake, PrabuEla, Spokje: [PHPUnit 10] @dataProvider methods must be declared static and public

Issue #2366129 by andypost, stefan.r, smustgrave, vacho: RegisterStreamWrappersPass and other have broken compiler pass for multiple tags

Issue #3404508 by mstrelan, smustgrave, quietone: Fix strict type errors in Functional tests: Add casts and fix types where needed

Issue #3417935 by mstrelan, acbramley: Remove calls to clearstatcache in \Drupal\Tests\file\Functional\FileFieldRevisionTest::testRevisions

Issue #3412464 by mstrelan, smustgrave: Fix strict type errors: Convert FormattableMarkup to strings (complex replacement) in core Functional tests

Issue #3384936 by marvil07, vbouchet, smustgrave, xjm, joachim: Use the API to set up languages in tests that are not specifically testing the language form

Issue #3404273 by mstrelan, smustgrave: Fix strict type errors: Convert FormattableMarkup to strings (simple replacement) in core Functional tests

Issue #3402295 by mstrelan, dww, smustgrave: Fix strict type errors in kernel tests: Add casts and fix types where needed

Issue #3410126 by kim.pepper, catch, larowlan, DamienMcKenna, alexpott: File validation logic from #3221793 broke backwards compatibility

Issue #2484991 by znerol, voleger, andypost, dww, anmolgoyal74, markdorison, ankithashetty, larowlan, daffie, alexpott: Add the session to the request in KernelTestBase, BrowserTestBase, and drush

Issue #3337295 by Akhil Babu, zniki.ru, rksyravi, quietone, harshitthakore, Indrapatil, smustgrave, longwave, poker10: Remove remaining uses of t() in assertEquals() calls