ldrpv2: slabinfo: Check poison markers on all slub objects

Validates redzone, padding, and poison markers for both allocated
and free objects.

Example output format:

Poison overwritten
INFO: 0xffffffc090546a30-0xffffffc090546a3f. First byte 0x0 instead of 0x6b
INFO: Object 0xffffffc090546a00 @offset=%a00 fp=0xffffffc090546f00

Bytes b4
ffffffc0905469f0: 5a5a 5a5a 5a5a 5a5a 5a5a 5a5a 5a5a 5a5a  ZZZZZZZZZZZZZZZZ
Object
ffffffc090546a00: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546a10: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546a20: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546a30: 006b 006b 600b 6b00 6b00 006b 6b00 6b00  .k.k`.k.k..kk.k.
ffffffc090546a40: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546a50: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546a60: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546a70: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546a80: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546a90: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546aa0: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546ab0: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546ac0: 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b 6b6b  kkkkkkkkkkkkkkkk
ffffffc090546ad0: 6b6b 6b6b 6b6b 6ba5                      kkkkkkk.

Change-Id: I2f784188f6f6990b1d3399d79f7ab9ef635e4835