Uninvert Japanese tests after fix to #8823

Uninvert Japanese tests after fix to #8823

The export ja/lilypond_pdf fails because ps2pdf gives an error. It
is thus still inverted, under the category 'externalissues'. As
Jürgen discovered, ps2pdf succeeds if the -dNOSAFER flag is used.

Note that Kornel is seeing strange behavior with the sweave test,
and thus the label of that test might be changed soon (e.g. to
"unreliable"). For discussion, see:

https://www.mail-archive.com/search?l=mid&q=20171001032524.fr5xfngylththwv2%40steph