RFR:8206009: Move java heap object archiving code to heapShared.hpp and heapShared.cpp

[Jiangli Zhou]

Please review the restructuring and cleanup of java heap object 
archiving code. The java object archiving code has grown in the past 
year and metaspaceShared.* files are not the suitable place. The 
restructuring and cleanup include:

   - Moved java heap object archiving implementation from 
metaspaceShared.* to heapShared.*.
   - Various is_archive_object() APIs are renamed to 
is_archived_object() for naming consistency:
      - Renamed MetaspaceShared::is_archive_object() to 
HeapShared::is_archived_object().
      - Renamed oopDesc::is_archive_object() to 
oopDesc::is_archived_object().
      - Renamed G1ArchiveAllocator::is_archive_object() to 
G1ArchiveAllocator::is_archived_object().
   - Changed to use G1ArchiveAllocator::is_archived_object() in 
G1CollectedHeap::materialize_archived_object(). Removed #include 
"memory/metaspaceShared.inline.hpp” from g1CollectedHeap.cpp.
   - Renamed HeapShared::archive_static_fields() to 
HeapShared::archive_object_subgraphs().

webrev: http://cr.openjdk.java.net/~jiangli/8206009/webrev.00/
RFE: https://bugs.openjdk.java.net/browse/JDK-8206009

Tested with tier1-tier3. Tier4 and tier5 are in progress.

Thanks,

Jiangli