vsprintf: dump full information of page flags in pGp

Currently the pGp only shows the names of page flags, rather than
the full information including section, node, zone, last cpupid and
kasan tag. While it is not easy to parse these information manually
because there're so many flavors. Let's interpret them in pGp as well.

To be compitable with the existed format of pGp, the new introduced ones
also use '|' as the separator, then the user tools parsing pGp won't
need to make change, suggested by Matthew. The new information is
tracked onto the end of the existed one.

On example of the output in mm/slub.c as follows,
- Before the patch,
[ 6343.396602] Slab 0x000000004382e02b objects=33 used=3 fp=0x000000009ae06ffc flags=0x17ffffc0010200(slab|head)

- After the patch,
[ 8448.272530] Slab 0x0000000090797883 objects=33 used=3 fp=0x00000000790f1c26 flags=0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff)

The documentation and test cases are also updated. The output of the
test cases as follows,
[68599.816764] test_printf: loaded.
[68599.819068] test_printf: all 388 tests passed
[68599.830367] test_printf: unloaded.

[lkp@intel.com: reported issues in the prev version in test_printf.c]

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: kernel test robot <lkp@intel.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210319101246.73513-4-laoar.shao@gmail.com