[DeLICM] Add regression tests for DeLICM reject cases.

[DeLICM] Add regression tests for DeLICM reject cases.

These tests were not included in the main DeLICM commit. These check the
cases where zone analysis cannot be successful because of assumption
violations.

We use the LLVM optimization remark infrastructure as it seems to be the
best fit for this kind of messages. I tried to make use if the
OptimizationRemarkEmitter. However, it would insert additional function
passes into the pass manager to get the hotness information. The pass
manager would insert them between the flatten pass and delicm, causing
the ScopInfo with the flattened schedule being thrown away.

Differential Revision: https://reviews.llvm.org/D30253

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@295846 91177308-0d34-0410-b5e6-96231b3b80d8