RFR: 8302789: (fs) File.copy should include unsupported copy option in exception message

[Christian Stein]

This PR also fixes the exception message for unsupported move options.

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Commit messages:
 - (fs) File.copy should include unsupported copy option in exception message

Changes: https://git.openjdk.org/jdk/pull/12625/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12625&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302789
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12625.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12625/head:pull/12625

PR: https://git.openjdk.org/jdk/pull/12625