(1) Bug fix that was causing nodes with dangling references to be freed.

    We run removeDeadNodes() on the TD graph up front before using it.
(2) Major enhancement to printing of results: now we list the actual objects
    that are mod/ref instead of just printing the bit vectors.
Also an important bug fix in TDDataStructures pass (no change here):
clear Mod/Ref bits of callers before inlining into a function.

llvm-svn: 4833