FROMGIT: kasan: add match-all tag tests

Add 3 new tests for tag-based KASAN modes:

1. Check that match-all pointer tag is not assigned randomly.
2. Check that 0xff works as a match-all pointer tag.
3. Check that there are no match-all memory tags.

Note, that test #3 causes a significant number (255) of KASAN reports
to be printed during execution for the SW_TAGS mode.

Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e
Link: https://lkml.kernel.org/r/da841a5408e2204bf25f3b23f70540a65844e8a4.1610733117.git.andreyknvl@google.com


Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
(cherry picked from commit 732aff980f14030413ced3af974de20b678c3850
 https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm)
(cherry picked from commit fef86ebc2b229a52021a1af1c227ac9a88e19cbe
 https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm)
(cherry picked from commit 55c0c48aa223d2a410ec68fc2f50af1369be7c78
 https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

 akpm)
Bug: 172318110
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Change-Id: Ie9d705c79bdfb38f8bdfe00e6b605dd06dc5fe84