Remove the FIXME I introduced last night, and pull the logic for

Remove the FIXME I introduced last night, and pull the logic for
marking selected overloads into the callers. This allows a few callers
to skip it altogether (they would have anyways because they weren't
interested in successful overloads) or defer until after further checks
take place much like the check required for PR9323 to avoid marking
unused copy constructors.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126503 91177308-0d34-0410-b5e6-96231b3b80d8