[OTS] Fix off-by-one in GSUB/GPOS parser

Use the number of cells in the sub-parser table for number of lookup type.

BUG=chromium:116524
TEST=ran test_{un,}malicious_fonts.sh
Review URL: http://codereview.chromium.org/9581044

git-svn-id: http://ots.googlecode.com/svn/trunk@83 a4e77c2c-9104-11de-800e-5b313e0d2bf3
2 files changed