RFR: 8337642: Serial: Remove redundant counter update in DefNewGeneration::gc_epilogue [v2]

[Albert Mingkun Yang]

> Trivial removing an empty method call. (Only subclasses have non-empty method body, which is not used by Serial.)

Albert Mingkun Yang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - review
 - Merge branch 'master' into s1-trivial
 - s1-trivial

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20416/files
  - new: https://git.openjdk.org/jdk/pull/20416/files/54f148df..86e46b66

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20416&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20416&range=00-01

  Stats: 4398 lines in 184 files changed: 2047 ins; 1389 del; 962 mod
  Patch: https://git.openjdk.org/jdk/pull/20416.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20416/head:pull/20416

PR: https://git.openjdk.org/jdk/pull/20416