RFR: 8312125: Refactor CDS enum class handling [v2]

[Ioi Lam]

> Please review this simple refactoring of the CDS code for handling enum classes. The code is moved to new files cdsEnumKlass.cpp/hpp. There's otherwise no change.

Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:

  fixed copyright

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20013/files
  - new: https://git.openjdk.org/jdk/pull/20013/files/64b77ecb..49dc109e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20013&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20013&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20013.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20013/head:pull/20013

PR: https://git.openjdk.org/jdk/pull/20013