RFR: 8344593: GenShen: Review of ReduceInitialCardMarks [v4]

[Y. Srinivas Ramakrishna]

> Fix documentation comment, and add an assertion check upon slowpath allocation.
> 
> I also checked the impact of +/-ReduceInitialCardMarks on GenShen using SPECjbb and didn't see any difference. We've left it enabled by default because less card marking is better in this case.

Y. Srinivas Ramakrishna has updated the pull request incrementally with one additional commit since the last revision:

  Demorganization of clause in assert per review feedback

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22507/files
  - new: https://git.openjdk.org/jdk/pull/22507/files/76ab8f3b..040b7e36

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22507&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22507&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/22507.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22507/head:pull/22507

PR: https://git.openjdk.org/jdk/pull/22507