Prune the back-edge components from cyclic composite glyphs in
sanitizeGlyphLocations (leaving non-cyclic siblings intact), reject OS/2
tables whose length is too short for the declared version so a clean
table gets regenerated, and upgrade a version 0.5 maxp table to 1.0 for
TrueType fonts to silence OTS' "wrong maxp version for glyph data".
It fixes#21298.