shelltest: downgrade #48 to a warning.
shelltest: downgrade #48 to a warning.

This is the test that
   x=y f
does *not* unset x after running f, if f is a shell function.  Apparently
that's the right thing to do, but freebsd dash 0.5.10.2 fails it.  This is
surprising because debian dash 0.5.8-2.4 passes, and it is presumably older.
Downgrade this to a warning because we want freebsd to have some cheap sh
variant that passes with redo, and nobody should be *relying* on this
insane behaviour anyway.

freebsd 11.2 sh (but not freebsd dash) fails test #24.  That one seems
rather serious, so I don't want to downgrade it to a warning.

apenwarr/redo,apenwarr/redo,apenwarr/redo,apenwarr/redo