RFR: 8350869: os::stat doesn't follow symlinks on Windows [v6]

[Anton Artemov]

> This PR addresses an issue on Windows, where a class file could not be loaded by a symbolic link. 
> 
> I added a check if a wide path is a symbolic link (soft one) and a method for dereferencing. Both os::stat() and os::open() on Windows now can handle such links.
> 
> Tested in tiers 1-3. A separate test added.

Anton Artemov has updated the pull request incrementally with one additional commit since the last revision:

  8350869: Fixed comments. Added skip exception to the test when symlinks are not supported.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25233/files
  - new: https://git.openjdk.org/jdk/pull/25233/files/f541fd6b..a6ff5001

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25233&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25233&range=04-05

  Stats: 25 lines in 2 files changed: 10 ins; 10 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/25233.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25233/head:pull/25233

PR: https://git.openjdk.org/jdk/pull/25233