Partially revert "GSocket: Fix race conditions on Win32 if multiple threads are waiting on conditions for the same socket"

Merged Silvio Lazzeretti requested to merge wip/silviol/gsocket_flags into master

This partially reverts commit 799f8dcd. This patch seems to break the writability status of the server socket: once somebody writes to it with success, then it reports it is not writable anymore. Also, when the client socket has the flag FD_CONNECT set once, it is never cleared and then it reports it is always writable, also when it is not.

Merge request reports