[PM] Port LVI to the new PM.

This is a bit gnarly since LVI is maintaining its own cache.
I think this port could be somewhat cleaner, but I'd rather not spend
too much time on it while we still have the old pass hanging around and
limiting how much we can clean things up.
Once the old pass is gone it will be easier (less time spent) to clean
it up anyway.

This is the last dependency needed for porting JumpThreading which I'll
do in a follow-up commit (there's no printer pass for LVI or anything to
test it, so porting a pass that depends on it seems best).

I've been mostly following:
r269370 / D18834 which ported Dependence Analysis
r268601 / D19839 which ported BPI

llvm-svn: 272593