tools/testing: add PROCMAP_QUERY helper functions in mm self tests

tools/testing: add PROCMAP_QUERY helper functions in mm self tests

The PROCMAP_QUERY ioctl() is very useful - it allows for binary access to
/proc/$pid/[s]maps data and thus convenient lookup of data contained
there.

This patch exposes this for convenient use by mm self tests so the state
of VMAs can easily be queried.

Link: https://lkml.kernel.org/r/ce83d877093d1fc594762cf4b82f0c27963030ee.1744104124.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>