[unittests] Add a test checking for a certain cmap
[unittests] Add a test checking for a certain cmap

Test for a specific cmap which is recommended by the OpenType spec:
format 4, platform ID 3 (Windows), encoding ID 1 (BMP). In general it
seems this table should always be present, even for platforms other
than Windows and fonts whose coverage extends beyond the BMP.

googlefonts/nototools,googlei18n/nototools,anthrotype/nototools,googlefonts/nototools,googlefonts/nototools,dougfelt/nototools,anthrotype/nototools,dougfelt/nototools,moyogo/nototools,dougfelt/nototools,anthrotype/nototools,moyogo/nototools,googlefonts/nototools,googlefonts/nototools,googlei18n/nototools,moyogo/nototools,googlei18n/nototools