RFR: 8374441: (fs) FileSystemProvider.readAttributesIfExists throws "Not a directory" when element in path is not directory should return null for ENOTDIR (unix) [v2]

[Fabian Meumertzheim]

> `FileSystemProvider.readAttributesIfExists` now returns `null` for a path with a true prefix that is not a directory rather than throwing `NotDirectoryException`.

Fabian Meumertzheim has updated the pull request incrementally with one additional commit since the last revision:

  Address review comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29013/files
  - new: https://git.openjdk.org/jdk/pull/29013/files/d7377abf..91f4b3ac

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29013&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29013&range=00-01

  Stats: 13 lines in 2 files changed: 6 ins; 2 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/29013.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29013/head:pull/29013

PR: https://git.openjdk.org/jdk/pull/29013