RFR: JDK-8325743: test/jdk/java/nio/channels/unixdomain/SocketOptions.java enhance user name output in error case

[Matthias Baesken]

In case of a bad running LDAP we got this output from test test/jdk/java/nio/channels/unixdomain/SocketOptions.java

java.lang.RuntimeException: wrong username
at SocketOptions.testPeerCred(SocketOptions.java:75)
at SocketOptions.main(SocketOptions.java:52)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1583)

It would be better to see the compared values (user name data we compare) and get them in the exception output.

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

Commit messages:
 - JDK-8325743

Changes: https://git.openjdk.org/jdk/pull/17829/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17829&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325743
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/17829.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17829/head:pull/17829

PR: https://git.openjdk.org/jdk/pull/17829