[sealed] JDK-8243582: JVMS change to class loading error

[Dan Smith]

In anticipation of sealed classes, JDK-8243582 describes a JVMS change that modifies an error thrown in class loading as of Java SE 16.

https://bugs.openjdk.java.net/browse/JDK-8243582

Specifically, VerifyErrors that were thrown during class loading due to `final` constraint violations will become IncompatibleClassChangeErrors. (And similarly, under `--enable-preview`, for `sealed` constraint violations.)

We feel like it's an appropriate change to make (class loading is not part of verification, and the handling of this check during verification in JVMS is just wrong), but want to make sure there aren't any concerns from a broader audience.