[skottie] Fix font style parsing

1) avoid partial matches (e.g. "Extra" vs. "ExtraLight")

2) weight/slant are space-separated (e.g. "ExtraLight Italic")

Change-Id: Id2db44d8b4a32b97674ec7490992974135b39ae9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/334164
Commit-Queue: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
3 files changed