[11u] RFR: 8212937: Parent class loader may not have a referred ClassLoaderData instance when obtained in Klass::class_in_module_of_loader

[Severin Gehwolf]

Hi,

Please review this 11u backport for JDK-8212937. While the JDK 12 patch
applies cleanly it doesn't quite do the right thing. The JDK 12 test
would still crash the JVM due to the lack of the changes in
src/hotspot/share/classfile/javaClasses.cpp as describe_external is
being used in JDK 11. That function has been removed with JDK-
8205611[1] in JDK 12.

In addition, the exception messages aren't the same between JDK 12 and
JDK 11, so Test.java needed an update to account for that. Also due to
lack of JDK-8205611[1] in JDK 11. Everything else is the same as for
JDK 12.

Bug: https://bugs.openjdk.java.net/browse/JDK-8212937
webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8212937/jdk11/webrev.01/

Testing: Added regression test, internal test.

Thoughts?

Thanks,
Severin

[1] https://bugs.openjdk.java.net/browse/JDK-8205611