swift234

Add MayBindDynamicSelf to CallGraphAnalysis.

Why did I choose to pollute the call graph? Because it's convenient,
efficient, and more robust than any current alternative.  This is a
property of the parent function that depends on all the call sites. We
need to cache this information somehow and update it whenever edges
are added to the call graph. The call graph does this perfectly.

The thing I don't like is that it is conservative and may not return a
precise answer after updates, which is generally undesirable. You
normally want to get the same answer whether you update or recompute
an analysis. Although this is generally bad, it is a good tradeoff
now. The need for this call graph property is a consequence of the
current SIL representation which should change soon. It only comes up
in bizarre corner cases, and the imprecision will never show up in
practice.

Swift SVN r28784