RFR: 8353950: Clipboard interaction on Windows is unstable [v6]

[Matthias Bläsing]

> - Introduce a lock into WClipboard that protects the code between
>   openClipboard/closeClipboard invocations.
>   The native side does not allow to open the clipboard multiple
>   times or share the opened clipboard between multiple threads.
> 
> - Remove of need to call openClipboard/closeClipboard from
>   getClipboardFormats by using the win32 call
>   GetUpdatedClipboardFormats
> 
> - Prevent a race-condition by not registering the connection
>   between java and native side of clipboard multiple time, but
>   just at construction time.

Matthias Bläsing has updated the pull request incrementally with one additional commit since the last revision:

  Limit running test only on windows

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/24614/files
  - new: https://git.openjdk.org/jdk/pull/24614/files/50ccf766..b9307454

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24614&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24614&range=04-05

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24614.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24614/head:pull/24614

PR: https://git.openjdk.org/jdk/pull/24614