Add benchmarks for large kernel matrix convolutions

Change-Id: I999881aae3666fa92d83a9cb23582d8fa3f5cf81
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/286998
Commit-Queue: Adlai Holler <adlai@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
1 file changed