RFR: 8349532: Refactor ./util/Pem/encoding.sh to run in java

[Mikhail Yankelevich]

* ./util/Pem/encoding.sh is now a java test
* also added the validations for the test results, not only an error check

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Commit messages:
 - JDK-8349532: Refactor ./util/Pem/encoding.sh to run in java

Changes: https://git.openjdk.org/jdk/pull/23492/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23492&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349532
  Stats: 90 lines in 2 files changed: 51 ins; 35 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/23492.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23492/head:pull/23492

PR: https://git.openjdk.org/jdk/pull/23492