core/test: simulate proper locking in run-mem_region test
core/test: simulate proper locking in run-mem_region test

Currently, this test doesn't do locking during region changes or
allocations. This change adds the appropriate locking.

Signed-off-by: Jeremy Kerr <68a658b44bbaefab3ef5cd231967195fc0ff9d69@ozlabs.org>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

stewart-ibm/skiboot,open-power/skiboot,csmart/skiboot,shenki/skiboot,shenki/skiboot,shenki/skiboot,legoater/skiboot,qemu/skiboot,open-power/skiboot,stewart-ibm/skiboot,stewart-ibm/skiboot,legoater/skiboot,qemu/skiboot,qemu/skiboot,ddstreet/skiboot,legoater/skiboot,csmart/skiboot,apopple/skiboot,open-power/skiboot,ddstreet/skiboot,csmart/skiboot,qemu/skiboot,legoater/skiboot,open-power/skiboot,mikey/skiboot,legoater/skiboot,qemu/skiboot,mikey/skiboot,open-power/skiboot,apopple/skiboot,ddstreet/skiboot,apopple/skiboot,mikey/skiboot,shenki/skiboot,shenki/skiboot