RFR(round 3): JDK-8048150: Allow easy configurations for large CDS archives

[Calvin Cheung]

This version of fix doesn't add another -XX option. Instead, we are 
counting the number of classes in the classlist file and estimate the 
size of various regions based on the number of classes.

Bug: https://bugs.openjdk.java.net/browse/JDK-8048150

webrev: http://cr.openjdk.java.net/~ccheung/8048150/webrev/

Test:
     JPRT
     jtreg on hotspot/runtime

thanks,
Calvin