MFV r353551: 10452 ZoL: merge in large dnode feature fixes

MFV r353551: 10452 ZoL: merge in large dnode feature fixes

illumos/illumos-gate@946342a260bbae359b48bf142ec1fe40792ee862
https://github.com/illumos/illumos-gate/commit/946342a260bbae359b48bf142ec1fe40792ee862

https://www.illumos.org/issues/10452
  illumos is missing a few small follow up ZoL bug fixes for the large dnode
  feature. We should pull those in.
  Those commits are in the ZoL tree as (newest to oldest):
  PR 8435 - 75d6b7ddca269542279975f716a343bb40a79baf - Add missing copyright
  notice to large_dnode tests
  PR 7433 - e14a32b1c844d924b9f093375c0badcf10f61741 - Fix object reclaim when
  using large dnodes
  PR 6616 - 48fbb9ddbf2281911560dfbc2821aa8b74127315 - Free objects when
  receiving full stream as clone
  PR 6695 - 39f56627ae988d09b4e3803c01c22b2026b2310e - receive_freeobjects()
  skips freeing some object

Portions contributed by: Ned Bass <bass6@llnl.gov>
Portions contributed by: Tom Caputi <tcaputi@datto.com>
Author: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Obtained from:	illumos, ZoL
MFC after:	2 weeks
X-MFC with:	r353176