Remove CFI diagnostics mode

CFI diagnostics sould be disabled since it introduces additional
overhead/complexity, and the diagnostics libraries haven't been analyzed
from a security perspective since they were primarily meant for testing.
The CFI will still work.

Bug: 146408702
Merged-In: I4403da7c2b893907ca48918142c98bb6211656e6
Change-Id: Iabe6ab844d09da7ff1db1b95595d097bf382931d
(cherry picked from commit 025ee10a)