lib: test_bitmap: add bitmap_print_bitmask/list_to_buf test cases

The added test items cover both cases where bitmap buf of the printed
result is greater than and less than 4KB.
And it also covers the case where offset for printing is non-zero
which will happen when printed buf is larger than one page in
sysfs bin_attribute.
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Link: https://lore.kernel.org/r/20210806110251.560-3-song.bao.hua@hisilicon.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>