RFR: 8342838: ECDHE algorithm can't be disabled for TLSv1.3 cipher suites

[Artur Barashev]

`SSLAlgorithmDecomposer.decomposes(CipherSuite.KeyExchange keyExchange)` method is missing the `null` case: TLSv1.3 cipher suites with ECDHE being used for both key exchange and authentication have `null` for KeyExchange object.

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Commit messages:
 - 8342838: ECDHE algorithm can't be disabled for TLSv1.3 cipher suites

Changes: https://git.openjdk.org/jdk/pull/21648/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21648&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342838
  Stats: 123 lines in 3 files changed: 92 ins; 4 del; 27 mod
  Patch: https://git.openjdk.org/jdk/pull/21648.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21648/head:pull/21648

PR: https://git.openjdk.org/jdk/pull/21648