Add diagnostic printfs and disable test # 4 on i386

Reviewed by: jmmv, rpaulo
MFC after: 3 days
Phabric: D749
PR: 191676
Sponsored by: EMC / Isilon Storage Division


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271349 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f