RFR: 8377339: Implement AOTCacheAccess::get_archived_object using heap roots [v2]

[Ioi Lam]

> The API `oop AOTCacheAccess::get_archived_object(int)` is used by the AOT compiler to access heap objects in the AOT cache.
> 
>  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 for this: `oop HeapShared::get_root(int index, ...)`
> 
> So we just need to make sure that all oops needed by the AOT compiler are all stored as heap roots.
> 
> This PR is intended to provide an acceptable solution in the short run to be used by the 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.
> 
> (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.)
> 
> Notes to reviewers
> - `HeapShared::archived_object_cache()` can now survive GCs that might happen during AOT compilation. I added a new function `HeapShared::archived_object_cache_hash()` with comments about how it uses `oop::identity_hash()`.
> - This code is added to make sure interned strings and method handles are roots
> 
>   if (AOTCodeCache::is_dumping_code() &&
>                (java_lang_invoke_MethodHandle::is_instance(obj) || is_interned_string(obj))) {
>       // Needed by AOT compiler.
>       append_root(obj);
>     }
> 
> - Also some clean up that's not necessary but nice to have:
>   - I removed the `DumpedInternedStrings` and replaced it with much simpler code.

Ioi Lam has updated the pull request incrementally with four additional commits since the last revision:

 - @DanHeidinga review comment
 - @DanHeidinga review comment
 - @DanHeidinga review comment
 - fixed typo

-------------

Changes:
  - all: https://git.openjdk.org/leyden/pull/108/files
  - new: https://git.openjdk.org/leyden/pull/108/files/33455b60..2cb0abb8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=leyden&pr=108&range=01
 - incr: https://webrevs.openjdk.org/?repo=leyden&pr=108&range=00-01

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/leyden/pull/108.diff
  Fetch: git fetch https://git.openjdk.org/leyden.git pull/108/head:pull/108

PR: https://git.openjdk.org/leyden/pull/108