[skottie] Add another text grouping test

TBR=

Change-Id: I9c1ca3e834fdc5b017446811db52582a326d777b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/274740
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed