HarfBuzz reports y-up, convert to y-down.

Change-Id: If90857f9cf8039ddc0dfba7f660d415a41953015
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/250818
Reviewed-by: Herb Derby <herb@google.com>
Reviewed-by: Julia Lavrova <jlavrova@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
1 file changed