RFR: 8268093: Manual Testcase: "sun/security/krb5/config/native/TestDynamicStore.java" Fails with NPE

[Weijun Wang]

The test must run with sudo but I forgot to mention it. New comment and a better error message is added.

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Commit messages:
 - 8268093: Manual Testcase: "sun/security/krb5/config/native/TestDynamicStore.java" Fails with NPE

Changes: https://git.openjdk.java.net/jdk/pull/4401/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4401&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268093
  Stats: 14 lines in 2 files changed: 12 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4401.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4401/head:pull/4401

PR: https://git.openjdk.java.net/jdk/pull/4401