[10] Review Request: 8189656 The Windows L&F should be moved out from the shared folder

[Sergey Bylokhov]

Hello.
Please review the fix for jdk10. This is the second attempt to move 
windows L&F from non-windows platforms. The first attempt JDK-6461834[1] 
was reverted because of JDK-8184813[2].
The root cause of those issue was fixed in JDK-8075255[3], and now we 
can move it again.

Bug: https://bugs.openjdk.java.net/browse/JDK-8189656
Webrev can be found at: http://cr.openjdk.java.net/~serb/8189656/webrev.02

The fix contains a few parts:
  - The code related to win l&f was moved from the "share" to the 
"windows" folder
  - The platform-specific export was moved from module-info.java to 
module-info.java.extra
  - A number of tests which use windows L&F were marked as windows-specific
  - The stub "ThemeReader.java" which was used to build win w&f on unix 
was removed.

[1] https://bugs.openjdk.java.net/browse/JDK-6461834
[2] https://bugs.openjdk.java.net/browse/JDK-8184813
[3] https://bugs.openjdk.java.net/browse/JDK-8075255

-- 
Best regards, Sergey.