Update hb_subset_repack_or_fail to new method signature that takes table tag.

[garretrieger]

No description provided.

[khaledhosny]

The test failure seems to be caused by changes in the message callbacks, please update the test expectations.

[anthrotype]

I guess it's a bit too late, but I think it might have been nicer or more pythonic to add an optional table_tag="" keyword argument to the existing repack method, instead of defining/exporting an additional repack_with_tag method in the public uharfbuzz API. I guess you did that to more closely match Harfbuzz's own C API.