Fix MSAN where glyphs are uninitialized in tests

Change-Id: I1d8874e1371ce2ddeba119b097d018ad94aa474c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/541016
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed