target CG node.  This allows the inliner to properly update the callgraph
when using the pruning inliner.  The pruning inliner may not copy over all
call sites from a callee to a caller, so the edges corresponding to those
call sites should not be copied over either.

This fixes PR827 and Transforms/Inline/2006-07-12-InlinePruneCGUpdate.ll

llvm-svn: 29120