Place the Integer.IntegerCache and cached Integer objects in the closed archive heap region

The Integer.IntegerCache and cached Integer objects are archived in the open archive heap region at CDS dump time (JDK-8209120). The Integer objects and the cache are good candidates for moving to the closed archived heap region for sharing. That was also suggested by Claes when he made the change for archiving the Integer.IntegerCache.

java.lang.Integer
- klass: 'java/lang/Integer'
- ---- fields (total size 2 words):
- private final 'value' 'I' @12 -128 (ffffff80)