RFR: 8240668 : G1 list of all PerRegionTable does not have to be a double linkedlist any more

[Ivan Walulya]

Hi all,

Please review this modification to change the list of all PerRegionTables from a double linkedlist to a linkedlist.

JBS: https://bugs.openjdk.java.net/browse/JDK-8240668
webrev: http://cr.openjdk.java.net/~iwalulya/8240668/00/

Testing: Tier 1 - 3

//Ivan