[skottie] Fix matrix parenting for default/static values

When all matrix properties are static/default, we simply discard the
matrix node.  But we cannot do that in the presence of a parent matrix.

TBR=
Change-Id: I56c62216f18786249dea063690261bfae83fabec
Reviewed-on: https://skia-review.googlesource.com/141127
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed