fix callgraph dump to not print 0x0x1234 for nodes.

Add the instruction pointer value for debuggability.  
We now get dump output that looks like this:

Call graph node for function: 'f1'<<0x1017086b0>>  #uses=1
  CS<0x1017046f8> calls external node

Call graph node for function: '_ZNSt6vectorIdSaIdEEC1EmRKdRKS0_'<<0x1017086f0>>  #uses=1
  CS<0x0> calls external node

Call graph node for function: 'f4'<<0x1017087a0>>  #uses=1
  CS<0x101708c88> calls function 'f3'

llvm-svn: 102194