[PM] Port ArgumentPromotion to the new pass manager.

Now that the call graph supports efficient replacement of a function and
spurious reference edges, we can port ArgumentPromotion to the new pass
manager very easily.

The old PM-specific bits are sunk into callbacks that the new PM simply
doesn't use. Unlike the old PM, the new PM simply does argument
promotion and afterward does the update to LCG reflecting the promoted
function.

Differential Revision: https://reviews.llvm.org/D29580

llvm-svn: 294667