Edje tests: Fix compilation warning

Thanks Stefan for the report.

I don't really like putting all those -DBLA_BETA or #define BLA_BETA
everywhere, though. Maybe the @beta flag is not required since the
EO APIs are still beta?

See: 0446619355

src/tests/edje/edje_test_edje.c

@@ -5,6 +5,8 @@
 #include <unistd.h>
 #include <stdio.h>
 
+#define EFL_GFX_FILTER_BETA
+
 #include <Eina.h>
 #include <Edje.h>