install/53610: sparc install fails with test(1) error

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         53610
>Category:       install
>Synopsis:       sparc install fails with test(1) error
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Sep 16 09:30:00 +0000 2018
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date 2018.09.14.22.08.49
>Organization:

>Environment:
System: NetBSD
Architecture: sparc
Machine: sparc
>Description:

The last few sparc installs on the TNF testbed have failed, for example:

  http://releng.netbsd.org/b5reports/sparc/2018/2018.09.14.22.08.49/install.log

The following messages appear in the console log (terminal escape
sequences edited out for readability):

  Command: /usr/mdec/binstall ffs /targetroot
  [: SMALL test, no fallback usage
  [: SMALL test, no fallback usage
  Cannot find "/targetroot" in mount table

>How-To-Repeat:

>Fix: