It makes compiler-rt tests fail if the gold plugin is enabled.

Revert "Rework interface for bitset-using features to use a notion of LTO visibility."
Revert "Driver: only produce CFI -fvisibility= error when compiling."
Revert "clang/test/CodeGenCXX/cfi-blacklist.cpp: Exclude ms targets. They would be non-cfi."

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@267871 91177308-0d34-0410-b5e6-96231b3b80d8