Fix unbounded stack usage warning in core/test/run-mem_region_release_unused_noalloc.c

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Silence warning for core/tests/stubs.c prlog missing prototype

We get the real prototype in real code from skiboot.h

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>