Moved helper macro to a discrete include file.

To help reduce code duplication and also 'kitchen-sink' includes
the ARRAY_LENGTH macro was moved to a stand-alone file and
referenced from the sources consuming it. Other macros will be
added in subsequent passes.

Signed-off-by: Jon A. Cruz <jonc@osg.samsung.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>

tests/ivi_layout-test.c

@@ -28,6 +28,7 @@
 #include <stdio.h>
 #include <string.h>
 
+#include "shared/helpers.h"
 #include "weston-test-client-helper.h"
 #include "ivi-application-client-protocol.h"
 #include "ivi-test.h"

tests/presentation-test.c

@@ -31,6 +31,7 @@
 #include <assert.h>
 #include <time.h>
 
+#include "shared/helpers.h"
 #include "weston-test-client-helper.h"
 #include "presentation_timing-client-protocol.h"
 

tests/vertex-clip-test.c

@@ -30,6 +30,7 @@
 
 #include "weston-test-runner.h"
 
+#include "shared/helpers.h"
 #include "src/vertex-clipping.h"
 
 #define BOUNDING_BOX_TOP_Y 100.0f

tests/weston-test-runner.h

@@ -31,6 +31,8 @@
 
 #include <stdlib.h>
 
+#include "shared/helpers.h"
+
 #ifdef NDEBUG
 #error "Tests must not be built with NDEBUG defined, they rely on assert()."
 #endif
@@ -44,8 +46,6 @@ struct weston_test {
 	int must_fail;
 } __attribute__ ((aligned (32)));
 
-#define ARRAY_LENGTH(a) ((int) (sizeof (a) / sizeof (a)[0]))
-
 #define TEST_BEGIN(name, arg)					\
 	static void name(arg)