message: Use op_base in mlir-tblgen test instead of extracted class.
  Avoid having to update the extracted classes and use the real op_base.td as
  input.
diff: -// RUN: mlir-tblgen -gen-rewriters %s | FileCheck %s
  +// RUN: mlir-tblgen -gen-rewriters -I %S/../../include %s | FileCheck %s
  -// Extracted & simplified from op_base.td to do more directed testing.
  -class TypeConstraint;
  -class Type : TypeConstraint {
  - code builderCall = ?;
  -}
  -class Pattern<dag patternToMatch, list<dag> resultOps> {
  - dag PatternToMatch = patternToMatch;
  - list<dag> ResultOps = resultOps;
  -}
  -class Pat<dag pattern, dag result> : Pattern<pattern, [result]>;
  -def ins;
  -class Op<string mnemonic> {
  - string opName = mnemonic;
  - dag arguments = (ins);
  -}
  -class Attr<Type t> {
  - Type type = t;
  - code storageType = ?;
  - code returnType = ?;
  -}
  +include "mlir/IR/op_base.td"
  // Create a Type and Attribute.
  def YT : Type {
  