Revert r49614. As Dan pointed out, some of these aren't correct.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49657 91177308-0d34-0410-b5e6-96231b3b80d8

tools/bugpoint/Miscompilation.cpp

@@ -657,7 +657,7 @@ static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
       for (Function::arg_iterator
              I = newMain->arg_begin(), E = newMain->arg_end(),
              OI = oldMain->arg_begin(); I != E; ++I, ++OI) {
-        I->takeName(OI);    // Copy argument names from oldMain
+        I->setName(OI->getName());    // Copy argument names from oldMain
         args.push_back(I);
       }