RFR: JDK-8290975 Minor cleanup could be done in javax.security

[Mark Powers]

https://bugs.openjdk.org/browse/JDK-8290975

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Commit messages:
 - second iteration
 - first iteration

Changes: https://git.openjdk.org/jdk/pull/9664/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9664&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290975
  Stats: 125 lines in 16 files changed: 7 ins; 24 del; 94 mod
  Patch: https://git.openjdk.org/jdk/pull/9664.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9664/head:pull/9664

PR: https://git.openjdk.org/jdk/pull/9664