The following API is used by the AOT compiler to access heap objects in the AOT cache.

   oop AOTCacheAccess::get_archived_object(int)

Because the objects can move in the production run, there's currently a complicated way to keep them alive using OopHandles.

https://github.com/openjdk/leyden/blob/6ce1832147ef3f01602b8fac02160038422a77bf/src/hotspot/share/cds/heapShared.cpp#L545-L610

However, we already have a mechanism that mapes an integer to an oop

    oop HeapShared::get_root(int index, ...)

So we just need to make sure that all objects needed by the AOT compiler are all stored as heap roots.

Proposals:

[1] (Done in this PR) In the short run (during initial AOT compiler integration into the mainline), the AOT compiler only needs the following objects

- a few common exception objects
- class loaders
- class mirrors
- interned strings
- method handles

Most of these objects are in the roots already. We just need to add interned strings and method handles into the heap roots.

[2] In the future, we should move the AOT compilation before we dump the heap. This way we know exactly what oops should be stored into the heap roots.