Cleanup of wxSocket::_Wait():

Cleanup of wxSocket::_Wait():
 - Rename to DoWait() to avoid symbols starting with underscores.
 - Added comments explaining how does it work.
 - Remove the pointless timeout manipulations: GSocket::Select() doesn't
   use timeout (any more?) anyhow.

Also pass GSOCK_LOST_FLAG to DoWait() from WaitForWrite() for the same reasons
it is done in WaitForRead().

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@56275 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775