[REVIEW][3-5] fdo#50169 crash in GraphiteLayout::expandOrCondense

[Michael Stahl]

this bug is marked as regression, crashes with STL assertion
(just a couple lines above the while loop where i've band-aided
a similar STL assertion with another bugdoc):

> error: attempt to subscript container with out-of-bounds index 6, but container only holds 6 elements. 

committed a trivial band-aid for this as well, at least doesn't
crash any more and valgrind doesn't complain.

http://cgit.freedesktop.org/libreoffice/core/commit/?id=b8452a89ceaa9008558b83f3a8b6937d14b7c803

would be nice if somebody had the time to investigate
whether these various vectors in this graphite code that i clearly don't
understand are sized properly.