test/memzone: handle previously allocated memzones

test/memzone: handle previously allocated memzones

Currently, memzone autotest expects there to be no memzones
present by the time the test is run. Some hardware drivers
will allocate memzones for internal use during initialization,
resulting in tests failing due to unexpected memzones being
allocated before the test was run.

Fix this by making sure all memzones allocated by this test
have a common prefix, and making callback increment a counter
on encountering memzones with this prefix. Also, separately
increment another counter that will count total number of
memzones left after test, and compares it to previously stored
number of memzones, to ensure that we didn't accidentally
allocated/freed any memzones we weren't supposed to. This
also doubles as a test for correct operation of memzone_walk().

Fixes: 71330483a193 ("test/memzone: fix memory leak")
Cc: stable@dpdk.org
Signed-off-by: Phil Yang <phil.yang@arm.com>
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Reviewed-by: Radoslaw Biernacki <radoslaw.biernacki@linaro.org>