use pragma warning push/pop under MSVC instead of enabling temporarily disabled warnings unconditionally (patch 1207689)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@34565 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/event.h

@@ -514,6 +514,7 @@ private:
 
 #ifdef __VISUALC__
     // 'this' : used in base member initializer list (for m_commandString)
+    #pragma warning(push)
     #pragma warning(disable:4355)
 #endif
 
@@ -580,7 +581,7 @@ private:
 };
 
 #ifdef __VISUALC__
-    #pragma warning(default:4355)
+    #pragma warning(pop)
 #endif
 
 #if WXWIN_COMPATIBILITY_2_4