rpm_load: Add irregular Java class file names to the end of the path

This ensures that the path is unique even if a ZIP file contains
multiple copies of a bit-wise identical class under different names.
database::add_dwarf(): Fix memory safety bug in DWARF string normalization

The rvalue-reference-with-default trick is definitely too cute.
Implement expiration of unreferenced DWARF producers
database: Enhance Java expiration to cover internal class paths