MFV r271223:

In dnode_sync(), do dnode_increase_indirection() before processing
the dn_next_nblkptr.

Illumos issue:
    5117 space map reallocation can cause corruption

MFC after:	3 days


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271226 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f