RFR: 8369995: Implement extra logging and/or propagate errors in X509KeyManagerImpl

[Mikhail Yankelevich]

In [JDK-8309667](https://bugs.openjdk.org/browse/JDK-8309667), there were issues with debugging due to no logging or throwing of errors by X509KeyManagerImpl::getEntry. [Line](https://github.com/openjdk/jdk/blob/6a4c2676a6378f573bd58d1bc32b57765d756291/src/java.base/share/classes/sun/security/ssl/X509KeyManagerImpl.java#L243-L245)

Extra logging and error propagating should be implemented for the X509KeyManagerImpl.

Thank you @djelinski for finding the issue and analysis.

-------------

Commit messages:
 - JDK-8369995: Implement extra logging and/or propagate errors in X509KeyManagerImpl

Changes: https://git.openjdk.org/jdk/pull/27851/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27851&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8369995
  Stats: 176 lines in 3 files changed: 163 ins; 2 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/27851.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27851/head:pull/27851

PR: https://git.openjdk.org/jdk/pull/27851