make check currently fails (beam-skip.ly, commit 7bcdd37be15ece09cd97841137b075a576bbe696)

[Reinhold Kainhofer]

The previous commit 7bcdd37be15ece09cd97841137b075a576bbe696 ("Fixes issue 
1706, issues a programming error at old assert error.") by Mike Solomon breaks 
make check, as the regtest issues lots of programming_error calls:

beam-skip.ly:17:33: Programmierfehler: must have Item for spanner bound of 
Beam
  \repeat "unfold" 24 { s8[ s ] s
                                 [ s]}

Cheers,
Reinhold

PS: If "make check" fails, it does not give ANY indication where it fails or 
how to get any information about the offending file. All it says is:

    Writing snippets...
    Processing...
    Processing /home/reinhold/lilypond/out/lybook-testdb/snippet-
names-1514509494.ly
   command failed: /home/reinhold/lilypond/out/bin/lilypond <snipped...>
   Child returned 1
   make[2]: *** [out-test/collated-files.texi] Error 1

Where and how can I find the information which of the hundreds of regtests  
caused the check to fail? snippet-names-1514509494.ly contains 584 files!
Shouldn't the build system (i.e. lilypond-book) provide better output (e.g. 
print the actual error to the command line)???
-- 
------------------------------------------------------------------
Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org