[AST] Adapt Polly to AnalysisSetTracker changes. NFC.

The method AliasSetTracker::getAliasSetForPointer was removed and replaced by AliasSetTracker::getAliasSetFor for the restructuring in r339930. 

Since Polly uses AliasSetTracker::getAliasSetForPointer, a temporary fix has been committed in r339937 with a comment:

     Can someone from polly please migrate usage and then delete the wrapper?

This commit is doing exactly that.

llvm-svn: 340072

include/llvm/Analysis/AliasSetTracker.h

@@ -399,13 +399,6 @@ public:
   /// set is returned.  
   AliasSet &getAliasSetFor(const MemoryLocation &MemLoc);
 
-  AliasSet &getAliasSetForPointer(Value *P, LocationSize Size,
-                                  const AAMDNodes &AAInfo) {
-    // This adapter exists so that polly can be updated to the new API.  Once
-    // done, please delete this.
-    return getAliasSetFor(MemoryLocation(P, Size, AAInfo));
-  }
-
   /// Return true if the specified instruction "may" (or must) alias one of the
   /// members in any of the sets.
   bool containsUnknown(const Instruction *I) const;