Fix Windows compile error

Windows was confusing the object's DestroyWindow with the system call
diff --git a/tests/vktestframework.cpp b/tests/vktestframework.cpp
index 5c526ba..5e1fbfa 100644
--- a/tests/vktestframework.cpp
+++ b/tests/vktestframework.cpp
@@ -105,7 +105,7 @@
     void InitPresentFramework(std::list<VkTestImageRecord> &imagesIn, VkInstance inst);
     void CreateMyWindow();
     VkFormat GetPresentFormat();
-    void DestroyWindow();
+    void DestroyMyWindow();
     void CreateSwapchain();
     void SetImageLayout(VkImage image, VkImageAspectFlags aspectMask,
                         VkImageLayout old_image_layout, VkImageLayout new_image_layout);
@@ -340,7 +340,7 @@
         vkPresent.InitPresentFramework(list, instance);
         vkPresent.CreateMyWindow();
         presentFormat = vkPresent.GetPresentFormat();
-        vkPresent.DestroyWindow();
+        vkPresent.DestroyMyWindow();
         return presentFormat;
     }
 }
@@ -1281,7 +1281,7 @@
 #endif
 }
 
-void TestFrameworkVkPresent::DestroyWindow()
+void TestFrameworkVkPresent::DestroyMyWindow()
 {
 #ifndef _WIN32
     xcb_destroy_window(m_connection, m_window);