linux(4): Implement close_range over native

Handling of the CLOSE_RANGE_UNSHARE flag is not implemented due to
difference in fd unsharing mechanism in the Linux and FreeBSD.

Reviewed by: mjg
Differential revision: https://reviews.freebsd.org/D39398
MFC after: 2 weeks

(cherry picked from commit 71bc17803edfaad545f0c1f1111ca892aed7a5c4)