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/drm_vma_limiter_cpu.c

@@ -54,7 +54,7 @@ struct intel_batchbuffer *batch;
 #define BO_ARRAY_SIZE 68000
 drm_intel_bo *bos[BO_ARRAY_SIZE];
 
-int main(int argc, char **argv)
+igt_simple_main
 {
 	int fd;
 	int i;
@@ -96,6 +96,4 @@ int main(int argc, char **argv)
 	drm_intel_bufmgr_destroy(bufmgr);
 
 	close(fd);
-
-	return 0;
 }