RFR: 8371284: GenShen: Avoid unnecessary card marking [v5]

[Nityanand Rai]

> Exclude young-young, old-old and honor UseCondCardMark in dirty card marking.

Nityanand Rai has updated the pull request incrementally with one additional commit since the last revision:

  hardening of comments
  
  remove unintended files

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/28204/files
  - new: https://git.openjdk.org/jdk/pull/28204/files/123078b2..4054a52e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28204&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28204&range=03-04

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/28204.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28204/head:pull/28204

PR: https://git.openjdk.org/jdk/pull/28204