alpha: Stop using 'inorder' and rely entirely on 'minor'

This patch avoids building the 'inorder' CPU model for any permutation
of ALPHA, and also removes the ALPHA regressions using the 'inorder'
CPU. The 'minor' CPU is already providing a broader test coverage.

ruby: rename MESI_CMP_directory to MESI_Two_Level

This is because the next patch introduces a three level hierarchy.