ScopDetection: Do not verify Aliasing

This does not work reliable and is probably not needed. I accidentally changed
this in this recent commit:

commit a0bcd63c6ffa81616cf8c6663a87588803f7d91c
Author: grosser <grosser@91177308-0d34-0410-b5e6-96231b3b80d8>
Date:   Thu Nov 10 12:47:21 2011 +0000

    ScopDetect: Use INVALID macro to fail in case of aliasing

    This simplifies the code and also makes the error message available to the
    graphviz scop viewer.

    git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@144284

llvm-svn: 144286