unicodejs: Update moveBreakOffset to include 'HebrewLetter' category

Follow up to I7a4729d0 where we upgrade to Unicode 6.3 with the new
'HebrewLetter' category but which wasn't added to our custom word break
cursoring implementation.

Bug: 64872
Change-Id: I3a99c7c54318e98ada5a6f632a0eda1cc3af1b73
Merge "unicodejs: Update moveBreakOffset to include 'HebrewLetter' category"