tests: Add gem_ctx_param_basic

Boring ioctl validation. Luckily no gaps found while doing it.

v2: git add ftw!

v3: Fixes:

- args->size is an outparam for get, adjust test.
- Pick an invalid param, not an invalid ioctl number ... tsk.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

tests/gem_ctx_exec.c

@@ -161,7 +161,8 @@ int fd;
 igt_main
 {
 	igt_skip_on_simulation();
-		igt_fixture {
+
+	igt_fixture {
 		fd = drm_open_any_render();
 
 		handle = gem_create(fd, 4096);