hg: jdk/sandbox: 8203354: assert in ClassLoader::update_module_path_entry_list() could have incorrect message

[chris.hegarty at oracle.com]

Changeset: 61657d4a99e5
Author:    ccheung
Date:      2018-05-24 09:15 -0700
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/61657d4a99e5

8203354: assert in ClassLoader::update_module_path_entry_list() could have incorrect message
Summary: Converting the assert in ClassLoader::update_module_path_entry_list() to a meaningful error message before aborting the CDS dump.
Reviewed-by: stuefe, iklam

! src/hotspot/share/classfile/classLoader.cpp
! test/hotspot/jtreg/runtime/appcds/jigsaw/modulepath/MainModuleOnly.java