RFR(M) 8234693 Consolidate CDS static and dynamic archive dumping code

[Ioi Lam]

https://bugs.openjdk.java.net/browse/JDK-8234693
https://cr.openjdk.java.net/~iklam/jdk16/8234693-consolidate-static-dynamic-cds-dump.v01/
https://wiki.openjdk.java.net/display/HotSpot/How+CDS+Copies+Class+Metadata+into+the+Archive

Currently there are two very similar implementations for static CDS archive
dumping (metaspaceShared.cpp) and dynamic CDS archive dumping 
(dynamicArchive.cpp).

I've merged the two versions and moved to a new file, archiveBuilder.cpp.

I also improved the copying algorithm to speed up dumping. Times for dumping
20000+ classes:

            static        dynamic
     Old    42.655 sec    67.014 sec
     New    37.027 sec    34.974 sec

Normally I would not try to optimize when refactoring code. I made an
earlier, naive attempt to use the old dynamic dumper for static dumping
(because dynamic dumping is essentially a superset of static dumping).
However, that caused significant regression in static dumping speed.

Hopefully the new algorithm is both faster and easier to understand.
Please see the wiki document for more information.

Tested with mach5 tiers 1-4.

Thanks
- Ioi