Run termination tests

[brawer]

Unicode’s test suite for text rendering engines now also contains a couple of test cases where any result is considered a success, as long as the rendering engine terminates within 3 seconds and does not crash. Perhaps harfbuzz wants to run those test cases too, in addition to those that check for a specific result. Currently, these test cases are GSUB-3, MORX-24 and MORX-34.

[behdad]

Yep, thanks. I'll add that feature to our test suite. We want to do the same about fuzzer-found tests (and then bulk-import them maybe). I also would expect much faster than 3s. 3s for such a short test is still DoS for browsers...

[behdad]

Implemented. We should update harfbuzz/test/shaping/data/text-rendering-tests/update.sh to generate new syntax from whatever syntax you choose for such tests.