[ScopInfo] Simplify new access functions under domain context

Summary:
We do not keep domain constraints on access functions when building the
scop. Hence, for consistency reasons, it makes also sense to not include
them when storing a new access function. This change results in simpler
access functions that make output easier to read.

This patch also helps to make DeLICMed memory accesses to be understood by
our matrix multiplication pattern matching pass. Further changes to the
matrix multiplication pattern matching are needed for this to work, so the
corresponding test case will be added in a future commit.

Reviewers: Meinersbur, bollu, gareevroman, efriedma, huihuiz, sebpop, simbuerg

Subscribers: pollydev, llvm-commits

Tags: #polly

Differential Revision: https://reviews.llvm.org/D35237

llvm-svn: 308215