Don't include outgoing embedding edges among the aliasing edges as
they do not contribute to the alias status of the aggregate in which
the node is embedded.

This change corrects errors where aggregates were mistakenly
classified as aliased, but fortunately with regards to compiler
correctness this only leads to missed optimization opportunities.

Make use of type information when tracking initial values during the
destructive update pass. Using argument type annotations allows the
find-initial-values phase of the pass to stop exploring impossible
value chains which previously lead to infinite loops which in turn
made the pass abort.