RFR: JDK-8232092 (fs) Files::isWritable returns false on a writeable root directory (win) [v9]

[Nhat Nguyen]

> I'm following up on the reviewing thread here: https://mail.openjdk.java.net/pipermail/nio-dev/2020-August/007456.html
> 
> All the tests that create symlinks are now properly checked against using `TestUtil.supportsLinks`

Nhat Nguyen has updated the pull request incrementally with one additional commit since the last revision:

  Update method name so that it's clearer

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/287/files
  - new: https://git.openjdk.java.net/jdk/pull/287/files/d9888e2c..2c8844c4

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=287&range=08
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=287&range=07-08

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/287.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/287/head:pull/287

PR: https://git.openjdk.java.net/jdk/pull/287