Currently the Windows-specific method ImplSalYieldMutexAcquireWithWait()
uses a messaging mechanism to learn about the SolarMutex being free again.
This is not reliable when the MessageQueue overflows (MS allows 10000
messages per queue). It is more safe to use MsgWaitForMultipleObjects.
This also allows to not only wait for the SolarMutex to be freed, but
also to detect when SendMessage() is used which needs to lead to a
reschedule to not block current Window handling.

Change-Id: Id317dda62aaa1fe7677d8d28929e6936e5a22705
Reviewed-on: https://gerrit.libreoffice.org/23921Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Armin Le Grand <Armin.Le.Grand@cib.de>