Enhance the ahead-of-time cache, which enables the HotSpot Java Virtual Machine to improve startup and warmup time, so that it can be used with any garbage collector, including the low-latency Z Garbage Collector (ZGC).

Prior to [JEP 516](https://openjdk.org/jeps/516), some of the AOT optimizations of the AOT cache introduced by [JEP 483: Ahead-of-Time Class Loading & Linking](https://openjdk.org/jeps/483) did not work when using ZGC because the state of objects could not be cached due to mapping the object state bit by bit from a file into the heap, which requires a common object format. The advanced memory layout of ZGC was incompatible with the simpler object format used by other GC implementations.

JEP 516 introduces a new way of loading objects in the background, instead of directly mapping memory from a file, which is compatible with all GC implementations. Hence, the full range of optimizations of the AOT cache is now available across all GC implementations, including ZGC.