RFR: 8356678: (fs) Files.readAttributes should map ENOTDIR to NoSuchFileException where possible (unix) [v3]

[Brian Burkhalter]

> Treat `ENOTDIR` as causing a `NoSuchFileException` instead of a `FileSystemExcception` in some places in order to handle cases such as a regular file named, for example, `foo/bar`.

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

  8356678: Revert some of the ENOTDIR changes and update test

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/25191/files
  - new: https://git.openjdk.org/jdk/pull/25191/files/fce26e50..0908e753

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25191&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25191&range=01-02

  Stats: 18 lines in 2 files changed: 5 ins; 11 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/25191.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25191/head:pull/25191

PR: https://git.openjdk.org/jdk/pull/25191