[Attributor] Remove notional overindexing check

AAPointerInfo currently bails on constant expression GEPs with
notional overindexing. I don't think this is necessary, as the
following code handling GEPOperator will deal with arbitrary
indices appropriately.

Differential Revision: https://reviews.llvm.org/D117203

Author: nikic

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

@@ -1182,7 +1182,7 @@ struct AAPointerInfoFloating : public AAPointerInfoImpl {
           return HandlePassthroughUser(Usr, OffsetInfoMap[CurPtr], Follow);
         if (CE->isCompare())
           return true;
-        if (!CE->isGEPWithNoNotionalOverIndexing()) {
+        if (!isa<GEPOperator>(CE)) {
           LLVM_DEBUG(dbgs() << "[AAPointerInfo] Unhandled constant user " << *CE
                             << "\n");
           return false;