madvise05: new testcase for Oops in madvise_willneed

This is a regression test for madvise(2) system call. It tests
kernel for NULL ptr deref Oops fixed by:
  commit ee53664bda169f519ce3c6a22d378f0b946c8178
  Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
  Date:   Fri Dec 20 15:10:03 2013 +0200
    mm: Fix NULL pointer dereference in madvise(MADV_WILLNEED) support

Signed-off-by: Jan Stancek <jstancek@redhat.com>
Acked-by: Caspar Zhang <caspar@casparzhang.com>
Acked-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>