FYI, starting to land patches to remove TerminatorInst

Just wanted to send an email to give folks a heads up.

Landing the patches got somewhat delayed due to security stuff, but I’m going to start making progress on it now.

For reference, the RFC thread is here:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123407.html

And the first and most interesting patch with a discussion of the specific commit plan and LGTM is here:
https://reviews.llvm.org/D47467