RFR: 8277159: Fix java/nio/file/FileStore/Basic.java test by ignoring /run/user/* mount points [v2]

[Alex Kasko]

> …/user/* mount points
> 
> The fix to the test is the same as in #5136 . The possible problem with this test was identified in [this comment](https://github.com/openjdk/jdk/pull/5136#issuecomment-900402107), however FileSystemException is thrown instead of NoSuchFileException in this case, thus the special check for "/run/user" is added.

Alex Kasko has updated the pull request incrementally with one additional commit since the last revision:

  remove bug id

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6399/files
  - new: https://git.openjdk.java.net/jdk/pull/6399/files/7c112e3c..f4c9973d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6399&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6399&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6399.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6399/head:pull/6399

PR: https://git.openjdk.java.net/jdk/pull/6399