Currently we have some restrictions if`-Djava.system.class.loader=` is specified

- we disable full module graph caching: https://github.com/openjdk/jdk/blob/0e223f1456c14efdb423595bee3444d5e26db7c6/src/hotspot/share/cds/cdsConfig.cpp#L286
- we disable loading cached classes for platform and system loaders: https://github.com/openjdk/jdk/blob/0e223f1456c14efdb423595bee3444d5e26db7c6/src/hotspot/share/cds/filemap.cpp#L1874-L1886

This is problematic for cases described in https://github.com/openjdk/jdk/pull/24223#discussion_r2034846610


Proposed fix:

We should extend the restrictions further
- At dump time, dump only boot classes (no platform, system or unregistered); disable AOTClassLinking
- At run time, load only boot classes (no platform, system or unregistered)