[LVI Printer] Rely on the LVI analysis functions rather than the LVI cache

Summary:
LVIPrinter pass was previously relying on the LVICache. We now directly call the
the LVI functions which solves the value if the LVI information is not already
available in the cache. This has 2 benefits over the printing of LVI cache:
1. higher coverage (i.e. catches errors) in LVI code when cache value is
invalidated.
2. relies on the core functions, and not dependent on the LVI cache (which may
be scrapped at some point).
It would still catch any cache invalidation errors, since we first go through
the cache.

Reviewers: reames, dberlin, sanjoy

Reviewed by: reames

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32135

llvm-svn: 304819