RFR: 8319373: Serial: Refactor dirty cards scanning during Young GC [v4]

[Albert Mingkun Yang]

> Reading the new code directly is probably easier. The structure is quite similar to its counterpart in Parallel.
> 
> It's mostly perf-neutral, except when dirty cards are scarce. Using `card_scan.java` in [JDK-8310031](https://bugs.openjdk.org/browse/JDK-8310031), I observed ~40% reduction in young-gc pause time with `stride = 32 * 64`.

Albert Mingkun Yang has updated the pull request incrementally with two additional commits since the last revision:

 - Update src/hotspot/share/gc/serial/cardTableRS.cpp
   
   Co-authored-by: Thomas Schatzl <59967451+tschatzl at users.noreply.github.com>
 - Update src/hotspot/share/gc/serial/cardTableRS.cpp
   
   Co-authored-by: Thomas Schatzl <59967451+tschatzl at users.noreply.github.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16492/files
  - new: https://git.openjdk.org/jdk/pull/16492/files/063e67ff..24cc1dec

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16492&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16492&range=02-03

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/16492.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16492/head:pull/16492

PR: https://git.openjdk.org/jdk/pull/16492