add wxYield to make sure all event was executed.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77837 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

tests/controls/slidertest.cpp

@@ -112,7 +112,7 @@ void SliderTestCase::LineUpDown()
     EventCounter linedown(m_slider, wxEVT_SCROLL_LINEDOWN);
 
     wxUIActionSimulator sim;
-
+    wxYield();
     m_slider->SetFocus();
 
     sim.Char(WXK_UP);
@@ -129,6 +129,7 @@ void SliderTestCase::LinePageSize()
 {
 #if wxUSE_UIACTIONSIMULATOR
     wxUIActionSimulator sim;
+    wxYield();
     m_slider->SetFocus();
 
     m_slider->SetPageSize(20);