MFC of 203763, 203764, 203768, 203769, 203770, 203782, and 203784.

MFC of 203763, 203764, 203768, 203769, 203770, 203782, and 203784.

These fixes correct a problem in the file system that treats large
inode numbers as negative rather than unsigned. For a default
(16K block) file system, this bug began to show up at a file system
size above about 16Tb.

These fixes also update newfs to ensure that it will never create a
filesystem with more than 2^32 inodes.

They also update libufs, tunefs, and growfs so that they properly
handle inode numbers as unsigned.

Reported by: Scott Burns, John Kilburg, and Bruce Evans
Followup by: Jeff Roberson
PR:          133980

git-svn-id: svn://svn.freebsd.org/base/stable/8@204375 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f