RFR: 8267820: (fs) Files.copy should attempt to copy POSIX attributes when target file in custom file system [v2]

[Brian Burkhalter]

> In `java.nio.file.Files.copy()` copy POSIX attributes even if the target is from a different file system provided both the source and target file systems support such attributes.

Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:

  8267820: Set permissions only, not owner nor group

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7627/files
  - new: https://git.openjdk.java.net/jdk/pull/7627/files/348c8867..beaf1754

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7627&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7627&range=00-01

  Stats: 5 lines in 1 file changed: 0 ins; 5 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7627.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7627/head:pull/7627

PR: https://git.openjdk.java.net/jdk/pull/7627