Initial implementation of S390 specific debug and IC functions.

R=danno@chromium.org,jkummerow@chromium.org,jochen@chromium.org,jyan@ca.ibm.com,michael_dawson@ca.ibm.com,mbrandy@us.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1743263003

Cr-Commit-Position: refs/heads/master@{#34400}