Unexpected hangs on tiny crafted files

[hongxuchen]

We found with our fuzzer that lepton 3f6d98c may spend too much time on some crafted files ( as listed in this directory). Given the fact that these file are quite small (<1k), we think this may result from some implementation pitfalls.

Command: lepton $FILE /tmp/test.jpg. When running lepton -unjailed $FILE /tmp/test.jpg, it exhibits several runtime errors.