RFR: 8186248 - Allow more flexibility in selecting Heap % of available RAM

[Bob Vandette]

Please review this updated webrev with changes suggested by David Holmes.

Webrev:

http://cr.openjdk.java.net/~bobv/8186248/webrev.02 <http://cr.openjdk.java.net/~bobv/8186248/webrev.02>

This CR https://bugs.openjdk.java.net/browse/JDK-8186248 <https://bugs.openjdk.java.net/browse/JDK-8186248> deprecates
the MaxRAMFraction, MinRAMFraction and InitialRAMFraction VM options
in JDK 10  and adds three new options which allow the user the ability to
select a percentage of available memory to be used for the Java Heap.

MaxRAMPercentage
MinRAMPercentage 
InitialRMAPercentage

Please let me know if anyone objects to the flag name and deprecation as I am in
the process of filing a CCC (CSR).

Thanks,
Bob.