d3d9/tests: Mark the test_cursor_pos() tests failing randomly on Windows as flaky.

dlls/d3d9/tests/device.c

@@ -5287,6 +5287,7 @@ static void test_cursor_pos(void)
     ok(ret, "Failed to set cursor position.\n");
     flush_events();
 
+    flaky
     ok((!expect_pos->x && !expect_pos->y) || broken(expect_pos - points == 7),
         "Didn't receive MOUSEMOVE %u (%ld, %ld).\n",
         (unsigned)(expect_pos - points), expect_pos->x, expect_pos->y);