[SCEV] Move ScalarEvolutionExpander.cpp to Transforms/Utils (NFC).

Authored by fhahn on May 20 2020, 2:08 AM.


[SCEV] Move ScalarEvolutionExpander.cpp to Transforms/Utils (NFC).

SCEVExpander modifies the underlying function so it is more suitable in
Transforms/Utils, rather than Analysis. This allows using other
transform utils in SCEVExpander.

This patch was originally committed as b8a3c34eee06, but broke the
modules build, as LoopAccessAnalysis was using the Expander.

The code-gen part of LAA was moved to lib/Transforms recently, so this
patch can be landed again.

Reviewers: sanjoy.google, efriedma, reames

Reviewed By: sanjoy.google

Differential Revision: https://reviews.llvm.org/D71537