tests: when running on valgrind, always return 0

tests/core/deprecated_buffer.c

@@ -162,5 +162,5 @@ int main(int argc, char **argv)
 
 	starpu_shutdown();
 
-	return ret;
+	STARPU_RETURN(ret);
 }

tests/core/deprecated_func.c

@@ -144,5 +144,5 @@ int main(int argc, char **argv)
 
 	starpu_shutdown();
 
-	return ret;
+	STARPU_RETURN(ret);
 }

tests/helper.h

@@ -49,3 +49,8 @@
 #  define STARPU_SKIP_IF_VALGRIND
 #endif
 
+#ifdef STARPU_HAVE_VALGRIND_H
+#  define STARPU_RETURN(ret) do { if(RUNNING_ON_VALGRIND) return 0; else return ret; } while(0)
+#else
+#  define STARPU_RETURN(ret) return ret
+#endif