RFR: 8370082: Intermediate objects clean up in ECDH, XDH, DHKEM, and HKDF [v2]

[Weijun Wang]

> Clean up more intermediate objects created during these operations.

Weijun Wang has updated the pull request incrementally with two additional commits since the last revision:

 - do not store key as bytes in XDH
 - add ECDH and XDH

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27921/files
  - new: https://git.openjdk.org/jdk/pull/27921/files/e84cf5c5..cdd81505

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27921&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27921&range=00-01

  Stats: 21 lines in 2 files changed: 15 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/27921.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27921/head:pull/27921

PR: https://git.openjdk.org/jdk/pull/27921