RFR: 8272773: Investigate making card table size configurable [v2]

[Vishal Chand]

> Hi,
> 
> Please review the changes to make CardTable entry size configurable. The changes primarily consists of:
> 
> 1. Addition of a cmdline flag **GCCardSizeInBytes** to make the card size startup time configurable.
> 2. Setting the card size based on the flag in G1, Parallel and Serial GC memory initialization paths.
> 3. Setting BlockOffsetTable size and ObjectStartArray size based on the card size.

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

  Changes as per the first set of comments

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5838/files
  - new: https://git.openjdk.java.net/jdk/pull/5838/files/c9d5203f..83062219

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5838&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5838&range=00-01

  Stats: 63 lines in 12 files changed: 34 ins; 8 del; 21 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5838.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5838/head:pull/5838

PR: https://git.openjdk.java.net/jdk/pull/5838