Remove the old tail duplication pass. It is not used and is unable to update

ssa, so it has to be run really early in the pipeline. Any replacement
should probably use the SSAUpdater.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138841 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/Scalar.cpp

@@ -63,7 +63,6 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeCFGSimplifyPassPass(Registry);
   initializeSimplifyLibCallsPass(Registry);
   initializeSinkingPass(Registry);
-  initializeTailDupPass(Registry);
   initializeTailCallElimPass(Registry);
 }