ObjectiveC migrator: Do not add explicit cf annotation for
cf functions which are CF_IMPLICIT_BRIDGING_ENABLED.
Add cf annotation to those not CF_IMPLICIT_BRIDGING_ENABLED
to reduce bridge casts.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189409 91177308-0d34-0410-b5e6-96231b3b80d8