Upgrade fonttools to 4.18.0 am: 7de6799fd4 am: f355cda65f am: 61f684e8f8

Original change: https://android-review.googlesource.com/c/platform/external/fonttools/+/1518214

Change-Id: Icf2878d08509880bf6b782ba11c4f9d89f3bde68