Core Text seems to apply them to Latin text, but Uniscribe doesn’t.

See https://github.com/harfbuzz/harfbuzz/pull/1908#issuecomment-521819343

Fixes https://github.com/harfbuzz/harfbuzz/issues/1907

* The ‘height’ needs to be negated since the API returns “distance from
  top to bottom side”.
* Similarly, the ‘y_offset‘ needs to be added to the height to get the
  ‘y_bearing’, since sbix’s offset is “the point in the glyph relative
  to its lower-left corner which corresponds to the origin” while
  ‘y_bearing’ is the “top side of glyph from origin”.

With these changes the sbix glyph metrics return values similar to other
tables, as they were otherwise unusable.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1592

Fixes https://github.com/harfbuzz/harfbuzz/issues/1541

Fixes https://github.com/harfbuzz/harfbuzz/issues/1556

Adjust tests.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1532

As run-tests.py already adds it

It is not visually noticeable but apparently affected by kern format2 correct implementation.
I should've checked CoreText result which can't as CircleCI outage.

Fixes #1235.

Ouch!

Follow-up to cf203af8

Fixes https://github.com/harfbuzz/harfbuzz/issues/1343

Fixes https://github.com/harfbuzz/harfbuzz/issues/1343

If we have duplicae font files in different directories, that would
break the oss-fuzz build currently.  So, rename some to avoid
name class with text-rendering-test.  Would be better to find
another solution.

Only merge when actual ligature happened.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1305