fusefs: copy_file_range must update file timestamps
If FUSE_COPY_FILE_RANGE returns successfully, update the atime of the
source and the mtime and ctime of the destination.
Reviewers: pfg
Differential Revision: https://reviews.freebsd.org/D33159
(cherry picked from commit 5169832c96451e0c939338d8ef34cd0875a24b83)