I don't think I broke anything.  Fuzzers will let me know..

I have no way to authoritatively know, but looks like test font only has one
face.  So, adjust test expectation instead.

Fixes https://github.com/harfbuzz/harfbuzz/pull/1085

I decided to always use the cache, instead of my previous sketch direction
that was to only allocate and use cache if fast advances are not available.
The cache is a mere 1kb, so just use it...

TODO: Invalidate cache on font size change.

Fixes https://github.com/harfbuzz/harfbuzz/issues/651
Fixes https://github.com/harfbuzz/harfbuzz/pull/1082

Useful for performance testing.

Not hooked to cairo yet.  Just changes shaping, not rasterization.

Meh.

Related to https://github.com/harfbuzz/harfbuzz/pull/1082

This reverts commit 473b17af.

Updates to recent changes.

Use rand=255 to mean "randomize".

Part of https://github.com/harfbuzz/harfbuzz/pull/803

Except if the set it to 1, which would mean "randomize"... Ugly.

Randomization only happens by default. If the user specifies a value for
'rand', that value is respected.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1141

New API:
HB_FEATURE_GLOBAL_START
HB_FEATURE_GLOBAL_END

Fix a bug in CBDT sanitize, and redundant check in avar.

Fix avar sanitize().