core.c: Fix compile warnings when simulator enabled (--enable-simulator)

src/core.c: In function #core_extract_handler#:
src/core.c:1377: warning: implicit declaration of function #core_orphan_adoption#
src/core.c:1396: warning: implicit declaration of function #core_dump_tree#

Signed-off-by: Hal Rosenstock <hal@mellanox.com>