RFR: 8343772: Expected IAPE not thrown in KDF.getInstance (TCK)

[Kevin Driver]

TCK/spec compliance fix for two `getInstance` methods in KDF - unwrap a wrapped IAPE from an NSAE.

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Commit messages:
 - JDK-8343772: Expected IAPE not thrown in KDF.getInstance (TCK)

Changes: https://git.openjdk.org/jdk/pull/21961/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21961&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343772
  Stats: 48 lines in 2 files changed: 25 ins; 5 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/21961.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21961/head:pull/21961

PR: https://git.openjdk.org/jdk/pull/21961