Blessed modifier order does not include sealed/non-sealed

[Pavel Rappo]

I couldn't find any prior discussions on this matter.

I noticed that bin/blessed-modifier-order.sh has not been updated for the [recently introduced](https://openjdk.org/jeps/409) `sealed` and `non-sealed` keywords. I also note that we already have cases in OpenJDK where those keywords are ordered differently. If we have a consensus on how to extend the "blessed order" onto those new keywords, I can create a PR to update the script.

-Pavel