RFR: 8325513: Export method for Cipher [v2]

[Weijun Wang]

> Add `Cipher::export` API.

Weijun Wang has updated the pull request incrementally with one additional commit since the last revision:

  rename

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18409/files
  - new: https://git.openjdk.org/jdk/pull/18409/files/8834f04e..b8658a76

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18409&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18409&range=00-01

  Stats: 3 lines in 2 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/18409.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18409/head:pull/18409

PR: https://git.openjdk.org/jdk/pull/18409