tests: roll out igt_simple_init/igt_simple_main

Also use igt_skip a bit more to simplify some of the tests.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

tests/gem_gtt_speed.c

@@ -59,6 +59,8 @@ int main(int argc, char **argv)
 	int loop, i, tiling;
 	int fd;
 
+	igt_simple_init();
+
 	igt_skip_on_simulation();
 
 	if (argc > 1)