Add a valgrind-art-host target to run the tests under valgrind.
Add a valgrind-art-host target to run the tests under valgrind.

Change-Id: I15b909891492776ff24e62423deadeaa72c38b18

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst