message: Remove derived attributes from tf.IfRegion and tf.WhileRegion op.
  These derived attributes are only necessary for export, where these ops will be converted to the functional form prior.
diff: @@ -338,10 +338,6 @@ else_branch: A region that computes the outputs of the op if cond = false.
  Variadic<TF_Tensor>:$output
  );
  - TF_DerivedOperandTypeAttr Tcond = TF_DerivedOperandTypeAttr<0>;
  - TF_DerivedOperandTypeListAttr Tin = TF_DerivedOperandTypeListAttr<1>;
  - TF_DerivedResultTypeListAttr Tout = TF_DerivedResultTypeListAttr<0>;
  -
  let regions = (region SizedRegion<1>:$then_branch, SizedRegion<1>:$else_branch);
  let verifier = [{
  @@ -755,8 +751,6 @@ def TL_WhileRegionOp : TF_Op<"WhileRegion",
  );
  let results = (outs Variadic<AnyTensor>:$output);
  - TF_DerivedOperandTypeListAttr T = TF_DerivedOperandTypeListAttr<0>;
  -
  let regions = (region SizedRegion<1>:$cond, SizedRegion<1>:$body);
  let verifier = [{ return Verify(*this); }];
  