remove the private hack from CallInst, it was not supposed to hit the branch anyway

as a positive consequence the CallSite::getCallee() methods now can be rewritten to be
a bit more efficient

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110380 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed