Fix dominatorForest calculation for SSA2

Copy 60efb65 "Fix dominatorForest calculation." to the SSA2
implementation of the dominatorForest.

It's also become apparent that the fakeRoot and fakeBlock just float
around after the dominator forest has been built, since they are a part
of the graph.  Another pass will have to be made to actually remove
these from the graph, in a later commit.
Convenience functions for SSA2 FunctionEntry

Copy the functions from b78d153 "Convenience functions." into SSA2;
uncomment the 'args' function.
SSA2: Make 'main' a FuncEntry, not a Func

During my initial pass converting the SSA2 IL to multi-entry functions,
I did not change the type of Program.main to a FuncEntry.  'main' needs
to be a FuncEntry, because 'FuncEntry's are now the the labels used for
intra-function transfers.
Copy SSA2 passes needed to convert ssa2.fun to multi-entry

These are all of the passes that are needed to build the Ssa2 functor.
All of them will have to be converted to multi-entry functions before a
MeSsa2 functor can be exported.

These files are here temporarily and will be removed once the
multi-entry pipeline is set-up and stable.
Convert SSA2 Analyze to the multi-entry SSA2 IL

The conversion was idential to:
70cf8a7 Convert SSA Analyze to the multi-entry SSA IL