RFR: 8183348: Better cleanup for jdk/test/sun/security/pkcs12/P12SecretKey.java [v2]

[Mikhail Yankelevich]

> * Changed the test to use scratch directory
> * Cleaned up the imports

Mikhail Yankelevich has updated the pull request incrementally with one additional commit since the last revision:

  changed file creation to use Utils.createTempFile

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Changes:
  - all: https://git.openjdk.org/jdk/pull/24718/files
  - new: https://git.openjdk.org/jdk/pull/24718/files/6496e9d7..44b39103

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24718&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24718&range=00-01

  Stats: 4 lines in 1 file changed: 3 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/24718.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24718/head:pull/24718

PR: https://git.openjdk.org/jdk/pull/24718