Core: Kill off Host_UpdateLogDisplay()

This was actually never used as far as I can tell. There was no wx event handling done whatsoever for the global ID, So this is basically a dead function.

Source/UnitTests/TestUtils/StubHost.cpp

@@ -16,7 +16,6 @@ void Host_ShowJitResults(unsigned int) {}
 void Host_Message(int) {}
 void* Host_GetRenderHandle() { return nullptr; }
 void Host_UpdateTitle(const std::string&) {}
-void Host_UpdateLogDisplay() {}
 void Host_UpdateDisasmDialog() {}
 void Host_UpdateMainFrame() {}
 void Host_GetRenderWindowSize(int&, int&, int&, int&) {}