ra: Persist path executable flag in FileState when replaying revisions
When a file is marked as executable through the use of the svn:executable property, that info must be persisted across replayed revisions.
Indeed, such a file can also be a svn link but when it is turned back to a regular file (by unsetting svn:special property and modifying its content) the execution rights should also be set on it as with a subversion export.
Without persisting the executable info, the execution rights will not be restored when such a case appears.
Related to #3695
Migrated from D6698 (view on Phabricator)