RFR: 8318096: Add getParams method in PublicKey and PrivateKey [v2]

[Weijun Wang]

> Add `getParams` to `PublicKey` and `PrivateKey` so it's available to all current and future public and private keys.
> 
> No test. Might add one.

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

  add spaces and code tags, and a test

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Changes:
  - all: https://git.openjdk.org/jdk/pull/16222/files
  - new: https://git.openjdk.org/jdk/pull/16222/files/9f2e4007..d0cf5c56

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16222&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16222&range=00-01

  Stats: 90 lines in 15 files changed: 62 ins; 0 del; 28 mod
  Patch: https://git.openjdk.org/jdk/pull/16222.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16222/head:pull/16222

PR: https://git.openjdk.org/jdk/pull/16222