RFR: 8194759: Support caching class mirror objects

[Jiangli Zhou]

Here is the new webrev with updates that address feedbacks from Misha, Ioi, Coleen and Thomas:

http://cr.openjdk.java.net/~jiangli/8194759/webrev.01/ <http://cr.openjdk.java.net/~jiangli/8194759/webrev.01/>

Incremental webrev:
http://cr.openjdk.java.net/~jiangli/8194759/webrev.01.inc/ <http://cr.openjdk.java.net/~jiangli/8194759/webrev.01.inc/>

Rerunning tiered testing ...

Thanks,
Jiangli