Add force_non_debuggable_final_build_for_compat

This flag forces the compat framework to assume we're on a
non-debuggable build, and use stricter rules for enforcing
the change id override policy.
On a non-debuggable build, this flag has no effect.

Test: atest OverrideValidatorImplTest
Bug: 158696818
Change-Id: I3b13f1898e7ff00580140debe2ced9f8074502ea