swift234

[g-arc-opts] Transpose the execution from processing a set of reference
counts a basic block at a time many times to processing a set of
reference counts on a function many times.

Now we have the final API for the analysis side of ARC, the API user
gets back:

1. The pointer being tracked.
2. A set of increments.
3. A set of decrements.
4. A set of increment insertion points.
5. A set of decrement insertion points.

<rdar://problem/16965332>

Swift SVN r18539