[TPM] Allow all tests of the xm test suite to be run when ACM

[TPM] Allow all tests of the xm test suite to be run when ACM
security is turned on in hypervisor. This is done by implicitly
labeling VMs and resources if they have not been labeled through
explicit calls.
To allow the xm tests suite to label resources automatically, run

./configure --enable-full-labeling

once. To turn it off, the '--enable-full-labeling' parameter should be
omitted.

Signed-off-by: Stefan Berger <stefanb@us.ibm.com>