RFR: 8209120: Archive the Integer.IntegerCache

[Claes Redestad]

Hi,

using the new ability to archive immutable heap graphs into the CDS 
archive, even archiving small things like the Integer.IntegerCache can 
be profitable.

Webrev: http://cr.openjdk.java.net/~redestad/8209120/open.00/

Bug: https://bugs.openjdk.java.net/browse/JDK-8209120

For a default cache (256 elements), this change saves us ~1 million 
instructions. Applications that use -XX:AutoBoxCacheMax can profit 
further (and we can use this to stress test the archiving feature..)

The patch is built on top of and tested with Jiangli's patch for 
https://bugs.openjdk.java.net/browse/JDK-8207263 and I don't intent to 
push this before that is in.

Thanks!

/Claes