RFR(M): jdk11u-dev backport 8205611: Improve the wording of LinkageErrors to include module and class loader information

[Lindenmaier, Goetz]

Hi,

I would like to backport 8205611. Unfortunately, it does not apply clean,
as 8212937, a fix that came after 8205611, was already downported.
I needed changes at two places:
Deleting obsolete java_lang_ClassLoader::describe_external() does
not apply because 8212937 changed in this function. See
http://cr.openjdk.java.net/~goetz/wr19/8205611-exMsg_LinkageError/webrev/src/hotspot/share/classfile/javaClasses.cpp.udiff.html
Further the exception message in duplicateParentLE/Test.java had to be adapted.

New webrev for 11u-dev:
http://cr.openjdk.java.net/~goetz/wr19/8205611-exMsg_LinkageError/webrev/
Original change:
http://hg.openjdk.java.net/jdk/jdk12/rev/bef02342d179
Original bug:
https://bugs.openjdk.java.net/browse/JDK-8205611

The conflicting change in jdk12:
http://hg.openjdk.java.net/jdk/jdk12/rev/de25152e5ec4
And downported to jdk11:
http://hg.openjdk.java.net/jdk-updates/jdk11u/rev/8687668b33da
https://bugs.openjdk.java.net/browse/JDK-8212937

See also the original review thread:
http://mail.openjdk.java.net/pipermail/hotspot-dev/2018-June/033325.html
http://mail.openjdk.java.net/pipermail/hotspot-dev/2018-July/033409.html

Best regards,
  Goetz.