git: openjdk/mobile: 8242241: add assert to ClassUnloadEventImpl::className

[duke]

Changeset: 68e0e49b
Author:    Serguei Spitsyn <sspitsyn at openjdk.org>
Date:      2020-04-13 18:02:13 +0000
URL:       https://git.openjdk.java.net/mobile/commit/68e0e49b

8242241: add assert to ClassUnloadEventImpl::className

Add assert

Reviewed-by: cjplummer, dcubed

! src/jdk.jdi/share/classes/com/sun/tools/jdi/EventSetImpl.java