RFR: 8277372: Add getters for BOT and card table members [v4]

[Vishal Chand]

> Changed the visibility, added getters and refactored the following:
> 
> 1. Card Table Members
> 2. BOT members
> 3. ObjectStartArray block members

Vishal Chand has updated the pull request incrementally with one additional commit since the last revision:

  Rename BOTConstants

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6570/files
  - new: https://git.openjdk.java.net/jdk/pull/6570/files/69ee4a32..48828873

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6570&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6570&range=02-03

  Stats: 93 lines in 9 files changed: 0 ins; 6 del; 87 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6570.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6570/head:pull/6570

PR: https://git.openjdk.java.net/jdk/pull/6570