Better test cases for IDSgrep user-defined predicates
IDSgrep is capable of reading, and detecting errors in, some very weird TTF/OTF cmap tables - for instance, those which contain invalid pointers despite having valid checksums; mapping tables in Microsoft-only format but describing Macintosh-only encodings; and files in a byte-swapped variant of TTF/OTF format (not as simple as just byte-swapping the whole file uniformly, because of differing field sizes). A lot of code in userpred.c will only execute in these weird cases, and is thus very hard to test. Ideally, we would have custom-made weird TTF/OTF files to get test coverage on that code; but building those will be a disproportionate amount of work.
bumping this to 0.7 because it's not critical and we need to get a new IDSgrep out into the wild