More cleanup on GrStrikeCache

I missed the comments on cl/260038; do them in this cl.

Change-Id: If3a842385c935ae7833ae9ead6ba527e4e9f11a9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/260096
Auto-Submit: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
2 files changed