Fix wxWakeUpIdle() in Unix console application broken by r71089.

Initialize m_pipeIsEmpty to true as we don't have anything in the pipe
initially and if this variable was false, nothing was ever written to the wake
up pipe and it was never set to true as nothing was read from it neither.

Closes #14166.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71442 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/evtloopunix.cpp

@@ -58,7 +58,7 @@ class PipeIOHandler : public wxFDIOHandler
 public:
     // default ctor does nothing, call Create() to really initialize the
     // object
-    PipeIOHandler() : m_pipeIsEmpty(false) { }
+    PipeIOHandler() : m_pipeIsEmpty(true) { }
 
     bool Create();