os2: make testnative working -- imported from bitwiseworks' fork:

https://github.com/bitwiseworks/SDL2-os2/commit/e2abc76b24c795051d0092cbd425544e73a0713e

test/testnativeos2.c

@@ -20,7 +20,7 @@ static void *CreateWindowNative(int w, int h);
 static void DestroyWindowNative(void *window);
 
 NativeWindowFactory OS2WindowFactory = {
-  "OS/2",
+  "DIVE",
   CreateWindowNative,
   DestroyWindowNative
 };