[aat] Correct array indexing when looking up actions in KerxSubTableFormat4 (#2539)

* [aat] Correct array indexing when looking up actions in KerxSubTableFormat4.

- For action_type 0 and 1, there are 2 values per action record; for action_type 2, there are 4. So we need to account for these factors when indexing into the ankrData array.

Fixes https://github.com/harfbuzz/harfbuzz/issues/2531.
2 files changed