Add a kludgey implementation of XTEST to go with the kludgey
implementation of XBEGIN.  Also kludge the CPUID output for AVX
capable targets so as to claim we support HTM.
Mark Wielaard, mjw@redhat.com)


git-svn-id: svn://svn.valgrind.org/vex/trunk@2776 8f6e269a-dfd6-0310-a8e1-e2731360e62c