RFR: 8333962: Obsolete OldSize [v2]

[Albert Mingkun Yang]

> Obsolete OldSize and related code. An internal variable `OldSize` is kept to capture the capacity of old-gen size.

Albert Mingkun Yang has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:

  obsolete-old-size

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Changes: https://git.openjdk.org/jdk/pull/19647/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19647&range=01
  Stats: 192 lines in 15 files changed: 7 ins; 168 del; 17 mod
  Patch: https://git.openjdk.org/jdk/pull/19647.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19647/head:pull/19647

PR: https://git.openjdk.org/jdk/pull/19647