[PATCH] CodeGen, SelectionDAG: Increase width of NumOperands and NumValues

[David Majnemer]

We discussed this on IRC but I'll repeat the conclusion our conclusion for the benefit of all.

SelectionDAGBuilder will attempt to create a `MERGE_VALUES` node with more than `USHRT_MAX` operands in order to turn our `ConstantArray` into an `SDNode`.

It has been determined that this is a correct fix but possible a costly one as it grows the size of `SDNode`.

For now, I will just add assertions to `SDNode`'s constructor to catch this a little eagerly instead of asserting later on in `SDValue`.

http://reviews.llvm.org/D6164