[infra] Minor refactor for recipe properties in gen_tasks

Change-Id: I76fb1e5da5dd162e8245758ccae8effac2f21c0d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/277179
Commit-Queue: Eric Boren <borenet@google.com>
Reviewed-by: Ravi Mistry <rmistry@google.com>
4 files changed