DynamicLoader: Cleanup test include files for Haiku

No need to use a different path from the BeOS one, which still works.

Change-Id: I7fe3e53ac6aaa7971eb22650935e80fa0bd41daa

testDynamicLoader.cxx

@@ -15,14 +15,10 @@
 #include KWSYS_HEADER(ios/iostream)
 #include KWSYS_HEADER(stl/string)
 
-#if defined(__BEOS__)
+#if defined(__BEOS__) || defined(__HAIKU__)
 #include <be/kernel/OS.h>  /* disable_debugger() API. */
 #endif
 
-#if defined(__HAIKU__)
-#include <os/kernel/OS.h>  /* disable_debugger() API. */
-#endif
-
 // Work-around CMake dependency scanning limitation.  This must
 // duplicate the above list of headers.
 #if 0