Make AffineMap::replaceDimsAndSymbols(...) const. This is also consistent with AffineExpr::replaceDimsAndSymbols func.

mlir/include/mlir/IR/AffineMap.h

public:
   /// This method substitutes any uses of dimensions and symbols (e.g.
   /// dim#0 with dimReplacements[0]) in subexpressions and returns the modified
   /// expression mapping.  Because this can be used to eliminate dims and
   /// symbols, the client needs to specify the number of dims and symbols in
   /// the result.  The returned map always has the same number of results.
   AffineMap replaceDimsAndSymbols(ArrayRef<AffineExpr> dimReplacements,
                                   ArrayRef<AffineExpr> symReplacements,
                                   unsigned numResultDims,
-                                  unsigned numResultSyms);
+                                  unsigned numResultSyms) const;
 
   /// Folds the results of the application of an affine map on the provided
   /// operands to a constant if possible.
   LogicalResult constantFold(ArrayRef<Attribute> operandConstants,
                              SmallVectorImpl<Attribute> &results) const;
 
   /// Propagates the constant operands into this affine map. Operands are
   /// allowed to be null, at which point they are treated as non-constant. This

mlir/lib/IR/AffineMap.cpp

 /// This method substitutes any uses of dimensions and symbols (e.g.
 /// dim#0 with dimReplacements[0]) in subexpressions and returns the modified
 /// expression mapping.  Because this can be used to eliminate dims and
 /// symbols, the client needs to specify the number of dims and symbols in
 /// the result.  The returned map always has the same number of results.
 AffineMap AffineMap::replaceDimsAndSymbols(ArrayRef<AffineExpr> dimReplacements,
                                            ArrayRef<AffineExpr> symReplacements,
                                            unsigned numResultDims,
-                                           unsigned numResultSyms) {
+                                           unsigned numResultSyms) const {
   SmallVector<AffineExpr, 8> results;
   results.reserve(getNumResults());
   for (auto expr : getResults())
     results.push_back(
         expr.replaceDimsAndSymbols(dimReplacements, symReplacements));
 
   return get(numResultDims, numResultSyms, results, getContext());
 }