RFR: 8350134: Get public key from EC private key in PKCS11

[Weijun Wang]

This code change adds support for getting public key from an EC private key in PKCS #11. This is is necessary to support DHKEM for keys in SunPKCS11. The support is still not complete and there is no way to get the public key if the private key is unwrapped from an encrypted form. PKCS #11 3.0 defined CKA_PUBLIC_KEY_INFO but I haven't yet found a library supporting it.

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Commit messages:
 - the code change

Changes: https://git.openjdk.org/jdk/pull/23651/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23651&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8350134
  Stats: 202 lines in 10 files changed: 166 ins; 10 del; 26 mod
  Patch: https://git.openjdk.org/jdk/pull/23651.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23651/head:pull/23651

PR: https://git.openjdk.org/jdk/pull/23651