chunkification and -native true

[Matthew Fluet]

> What is the correct chunkification strategy to use with -native true? 

I thought it was decided that ChunkPerFunc was the right strategy.

I think that OneChunk would really slow down the backend, if only from a
memory standpoint, because the entire program would need to be translated
to pseudo-assembly.  The only other place where the size of the chunk
mattered was in patching up liveness, but that seems like its on its way
to being resolved.