Before this change, the compilePoints() routine would wrongly clear
the most-significant bit of the lower byte in its binary output.
An example glyph affected by this bug was “perthousand.oldstyle” in
the version of Skia.ttf that Apple ships with MacOS X Yosemite 10.10.3.
Although the broken code path was exercised in the unit tests, the
length of the test input just happened to have the affected bit clear,
which is why this bug did not get caught by the previous test cases.
f121b070f7