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_render_linear_blits.c

@@ -73,6 +73,8 @@ int main(int argc, char **argv)
 	uint32_t start = 0;
 	int i, j, fd, count;
 
+	igt_simple_init();
+
 	fd = drm_open_any();
 
 	render_copy = get_render_copyfunc(intel_get_drm_devid(fd));