Remove unused buffer methods

Remove glyphs from the variant. It's not really a variant
anymore, but will be removed in future CLs.

Remove tests for parts of the buffer system that no longer
are used.

bug: skia:14065
Change-Id: Ie188252e40c33901ef4ea80d16a3cac7a6c73d78
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/644037
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Herb Derby <herb@google.com>
3 files changed