RFR: 8264152: javax/net/ssl/DTLS/RespondToRetransmit.java timed out

[Fernando Guallini]

test/jdk/javax/net/ssl/DTLS/RespondToRetransmit.java has been seen to fail intermittently. 
The server side is binding to the wildcard/localhost address which has been a source of instability in many tests. Binding to loopback address fixes the intermittent failures.

In addition, other changes were introduced in the tests to improve code readability:
- Reduce duplication by reusing code
- Replace if statements with Switch expressions
- Make fields final when appropriate
- Convert ServerCallable and ClientCallable to records
- Replace Byte.valueOf with Byte.parseByte to avoid redundant boxing

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

Commit messages:
 - renamed constants field
 - fix intermittent time out, refactor

Changes: https://git.openjdk.java.net/jdk/pull/3466/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3466&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8264152
  Stats: 300 lines in 3 files changed: 78 ins; 130 del; 92 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3466.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3466/head:pull/3466

PR: https://git.openjdk.java.net/jdk/pull/3466