Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r238198 (by trasz):
Fix orphan() methods of several GEOM classes to not assume that there
is an error set on the provider. With GEOM resizing, class can become
orphaned when it doesn't implement resize() method and the provider size
decreases.

MFC 229537

GEOM_UNCOMPRESS module, can be used with uzip images and with new ulzma images.

GEOM_UNCOMPRESS module, can be used with uzip images and with new ulzma images.

Approved by: adrian (mentor)