RFR: 8367344: Better error message when decryption of AP-REQ fails because of kvno mismatch [v5]

[Weijun Wang]

> For interoperability, AP-REQ decryption uses the key with the highest kvno in the keytab if no exact match is found. If decryption fails, a normal "checksum failed" error is reported, which may hide the real cause that the wrong key is used. This code change throws a KRB_AP_ERR_BADKEYVER error in this case.
> 
> The change is only made in AP-REQ decryption to minimize impact. A previous test is enhanced to cover the case.

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

  call fromUserKtab directly with aotomatic isInitiator being false; show exception if not correct code

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27298/files
  - new: https://git.openjdk.org/jdk/pull/27298/files/10e409d6..aee6aec3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27298&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27298&range=03-04

  Stats: 17 lines in 1 file changed: 0 ins; 4 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/27298.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27298/head:pull/27298

PR: https://git.openjdk.org/jdk/pull/27298