#5801 crash from page-turn-breaking

[Han-Wen Nienhuys]

lilypond boom
GNU LilyPond 2.21.0
Processing boom.ly' Parsing... Interpreting music...[8][16][24][24] Preprocessing graphical objects... Calculating page and line breaks (2 possible page breaks)...lilypond: page-turn-page-breaking.cc:222: void Page_turn_page_breaking::calc_subproblem(vsize): Assertion!std::isinf (best.demerits_) && start < end - 1' failed.
Aborted (core dumped)

[Thomas Morley]

FWIW, an even more minimal example would be:

\version "2.21.0"

\layout {
  \context {
    \Staff
    \consists "Page_turn_engraver"
  }
}

\paper {
  page-breaking = #ly:page-turn-breaking
}

\new Voice  { \bar "||" r1 b }

With the same paper and layout as above, this fails as well:

\new Voice  { \pageBreak b }