make POSIX and Windows implementation of wxThread::Run() coherently assert when trying to Run() a thread twice; add a test for it.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65106 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/thread.cpp

@@ -1077,11 +1077,8 @@ wxThreadError wxThread::Run()
 {
     wxCriticalSectionLocker lock(m_critsect);
 
-    if ( m_internal->GetState() != STATE_NEW )
-    {
-        // actually, it may be almost any state at all, not only STATE_RUNNING
-        return wxTHREAD_RUNNING;
-    }
+    wxCHECK_MSG( m_internal->GetState() == STATE_NEW, wxTHREAD_RUNNING,
+             wxT("thread may only be started once after Create()") );
 
     // the thread has just been created and is still suspended - let it run
     return Resume();