Added break statements to various default: cases

No behavioral changes, just stylistic.

Change-Id: I95a54bb2ee5610272ecea4886163ba79ae2544a2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/447837
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
6 files changed