Simplify optimization flags in a bunch of FPs

ProcessorOptimzationFlags already returns kAll for null children

Change-Id: Iff29d1a2bfd4d6a3aaa7359f3003b757fdef8ccb
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/402649
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
27 files changed