RFR: 8282621: G1: G1SegmentedArray remove unnecessary template parameter [v4]

[Ivan Walulya]

> Hi all,
> 
> Please review this refactoring change to remove unnecessary template parameters. The change has two commits, one to remove the template parameter, this allows for the second clean up to hoist `G1CardSetAllocator` parameter independent methods and variables into a base class.
> 
> Testing: Tier 1.

Ivan Walulya has updated the pull request incrementally with one additional commit since the last revision:

  kim review: cleanup

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7689/files
  - new: https://git.openjdk.java.net/jdk/pull/7689/files/044a15af..fdb75011

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7689&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7689&range=02-03

  Stats: 63 lines in 4 files changed: 17 ins; 37 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7689.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7689/head:pull/7689

PR: https://git.openjdk.java.net/jdk/pull/7689