RFR: 8367309: Test runtime/os/windows/TestAvailableProcessors.java fails to compile after mis-merge

[David Holmes]

Restored the deleted imports. Removed an unneeded import.

Thanks

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Commit messages:
 - 8367309: Test runtime/os/windows/TestAvailableProcessors.java fails to compile after mis-merge

Changes: https://git.openjdk.org/jdk/pull/27186/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27186&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367309
  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27186.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27186/head:pull/27186

PR: https://git.openjdk.org/jdk/pull/27186