This reverts commit 3d8c1598, and
instead, checks if the MtaOleReq window is not destroyed yet, in
addition to the wait for the condition. This allows to avoid wait
forever for condition which never gets signalled, and process the
sent messages when waiting.

The window's WM_DESTROY handler sets the event signalling that.
The Win32Condition's wait() is changed to take the abort event,
and return true if its own event fired, and false if abort event
fired.

Change-Id: I1861dd3dabb39329976a3ccf2a5392c9ddbf9613
Reviewed-on: https://gerrit.libreoffice.org/67383
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>