to reflect the fact that they actually operate on arbitrary nodes
* Clean up public interface of FunctionDSGraph
* add getEscapingAllocations & getNonEscapingAllocations
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2019 91177308-0d34-0410-b5e6-96231b3b80d8