Cleanup usages of CreateConfiguredJarList

After previous refactorings the CreateConfiguredJarList function is now
only used in tests and are supplied with a PathContext that will cause
ReportPathErrorf() to panic. So, this change removes the ctx parameter,
calls panic directly on any error and renames the method to make it
clear that it is for testing only.

Bug: 171479578
Test: m nothing
Change-Id: Icfb4bdfe720afa855b64ecf0e74a0b030882d029