Spectre cross process (spectreXP)

This is Riverside Research's spectreXP as described in the ICCWS '22 paper: "Transient Execution and Side Channel Analysis: a Vulnerability or a Science Experiment?"

Notes:

1. attack and victim need to be pinned to same core
2. demo.sh runs both attack and victim in one
3. run make after changing victim or attacker process to rebuild

Author: Michael Shepherd