Revert "Disable pointer authentication in app processes."

Revert "Disable pointer authentication in app processes."

Revert "[automerged blank] Disable pointer authentication in app..."

Revert submission 16712509-sc-dev-I3030c47be9d02a27505bd4775c1982a20755758c-sc-v2-dev

Reason for revert: PAC has shipped with S, and we're going with app compat outreach rather than regressing security.
Reverted Changes:
I3030c47be:Disable pointer authentication in app processes.
I3030c47be:Disable pointer authentication in app processes.
I84a696428:[automerged blank] Disable pointer authentication ...
Ibc52deaf3:[automerged blank] Disable pointer authentication ...

Change-Id: I7ebdfce99ef6387415eb21cd216344b8eaf64b61