RFR: 8359340: KRB5 tests should protect themselves against random proxy selection

[Mikhail Yankelevich]

1. KRB5 tests is now always selecting NO_PROXY. 
2. test cleanup

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

Commit messages:
 - 8359340: KRB5 tests should protect themselves against random proxy selection
 - Merge branch 'master' into JDK-8359340
 - test cleanup

Changes: https://git.openjdk.org/jdk/pull/26061/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26061&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8359340
  Stats: 53 lines in 1 file changed: 4 ins; 22 del; 27 mod
  Patch: https://git.openjdk.org/jdk/pull/26061.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26061/head:pull/26061

PR: https://git.openjdk.org/jdk/pull/26061