dnn: fix compilation of Halide tests

modules/dnn/perf/perf_halide_net.cpp

@@ -5,6 +5,8 @@
 // Copyright (C) 2017, Intel Corporation, all rights reserved.
 // Third party copyrights are property of their respective owners.
 
+#include "perf_precomp.hpp"
+
 namespace cvtest
 {
 

modules/dnn/test/test_halide_layers.cpp

@@ -8,6 +8,8 @@
 // This tests doesn't require any external data. They just compare outputs of
 // layers using different computation backends. Input and parameters are random.
 
+#include "test_precomp.hpp"
+
 namespace cvtest
 {
 

modules/dnn/test/test_halide_nets.cpp

@@ -5,6 +5,8 @@
 // Copyright (C) 2017, Intel Corporation, all rights reserved.
 // Third party copyrights are property of their respective owners.
 
+#include "test_precomp.hpp"
+
 namespace cvtest
 {