RFR: 8329766: Serial: Refactor SerialBlockOffsetTable API [v2]

[Albert Mingkun Yang]

> Simple refactoring towards unifying BOT API between Serial and Parallel.

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-bot-api
 - s1-bot-api

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18651/files
  - new: https://git.openjdk.org/jdk/pull/18651/files/3ca3eaba..18cd69f0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18651&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18651&range=00-01

  Stats: 2102 lines in 84 files changed: 848 ins; 1044 del; 210 mod
  Patch: https://git.openjdk.org/jdk/pull/18651.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18651/head:pull/18651

PR: https://git.openjdk.org/jdk/pull/18651