Update fontchain_lint.py to read Emoji 5.0 data

This corresponds to an update in emoji-zwj-sequences.txt in
I956ba139737bd79f5e31324ed77df9182342df4e.

Test: The updated script passes with the update data file.
Bug: 30999328
Change-Id: I989dee6e571645daa324ae3eb667e3a92a31511f