Issue #2526412 by neclimdul, hussainweb, Fabianx: Remove Singleton hack in registerWithSymfonyGuesser

Issue #2392559 by mondrake, mitrpaka, JeroenT, rpayanm, adci_contributor, ianthomas_uk: Remove all uses of file_stream_wrapper_get_* and file_get_stream_wrappers

Issue #2408371 by dawehner, Fabianx, alexpott, bforchhammer: Proxies of module interfaces don't work

Issue #2050759 by tim.plunkett, fietserwin: Move drupal_chmod and other code in file.inc to a Drupal\Core\File\FileSystem class

Revert "Issue #2388749 by alexpott, adci_contributor, ParisLiakos: Register symfony's mime guessers if they are supported"

This reverts commit 4dae1d99.

Issue #2388749 by alexpott, adci_contributor, ParisLiakos: Register symfony's mime guessers if they are supported

Issue #2387443 by alexpott, dawehner: BinaryFileResponse can fail because the core MIME guessing is not added to the MimeType singleton