Add null guard to intrinsic evaluation of normalize().

Bug: oss-fuzz:58878
Change-Id: Idf2778137d0f04912991b0fef6cadaac43c63c7a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/697337
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2 files changed