add pixel xl to skpbench

Change-Id: I931292a74e39eb06715ce3dde6a4662474a23df6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/322322
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Herb Derby <herb@google.com>
1 file changed