RFR: 8069345: (fs) FileTreeWalker throws NotDirectoryException on file junction points [v3]

[Brian Burkhalter]

> Improve support for Windows directory junctions.

Brian Burkhalter has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge
 - 8069345: Add os.family == windows to tests
 - 8069345: (fs) FileTreeWalker throws NotDirectoryException on file junction points

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21555/files
  - new: https://git.openjdk.org/jdk/pull/21555/files/7d9067f3..deca8f8e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21555&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21555&range=01-02

  Stats: 586412 lines in 9415 files changed: 318885 ins; 214759 del; 52768 mod
  Patch: https://git.openjdk.org/jdk/pull/21555.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21555/head:pull/21555

PR: https://git.openjdk.org/jdk/pull/21555