RFR: 8327002: (fs) java/nio/file/Files/CopyMoveVariations.java should be able to test across file systems

[Brian Burkhalter]

1. Modify the test to allow specifying the location of the temporary directory to be distinct from that of the working directory.
2. Correctly handle the responses to `AccessDeniedException`s which occur when a move across different file systems fails.

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Commit messages:
 - 8327002: (fs) java/nio/file/Files/CopyMoveVariations.java should be able to test across file systems

Changes: https://git.openjdk.org/jdk/pull/18052/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18052&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327002
  Stats: 39 lines in 1 file changed: 27 ins; 0 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/18052.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18052/head:pull/18052

PR: https://git.openjdk.org/jdk/pull/18052