introduce a new CallGraphSCC class, and pass it around

to CallGraphSCCPass's instead of passing around a
std::vector<CallGraphNode*>.  No functionality change,
but now we have a much tidier interface.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101558 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/VMCore/PassManagerTest.cpp

@@ -154,7 +154,7 @@ namespace llvm {
 
     struct CGPass : public PassTest<CallGraph, CallGraphSCCPass> {
     public:
-      virtual bool runOnSCC(std::vector<CallGraphNode*> &SCMM) {
+      virtual bool runOnSCC(CallGraphSCC &SCMM) {
         EXPECT_TRUE(getAnalysisIfAvailable<TargetData>());
         run();
         return false;