<AWT Dev> RFR: 8252679: Two windows specific FileDIalog tests may fail on some Windows_Server_2016_Standard

[Sergey Bylokhov]

These seemingly simple checks are needed on Windows because on windows we allow navigating in the special
folders(Libraries). To map the LIbrary such as Music/Video we call the native win32 API. If this API fails to convert
the Library to the path, we will show this library to the user in the FileChooser without an ability to navigate it.

I have checked that the test fails on the systems where the native API sometimes cannot map the Library to the path, so
even the native applications cannot navigate it.

We run these tests, as a service on the headless windows system, so this could be a reason.

For now, I would like to move these tests to the headful group where we know the desktop session exists. If they
continue to fail we probably will need to relax the checks in the tests.

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Commit messages:
 - Run these tests on the headful systems only

Changes: https://git.openjdk.java.net/jdk/pull/24/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=24&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8252679
  Stats: 6 lines in 2 files changed: 5 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/24.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/24/head:pull/24

PR: https://git.openjdk.java.net/jdk/pull/24