message: Remove NoSideEffect trait from TensorFlow PlaceholderInputOp
  This will preserve attributes even if the input is unused. TFLite InputOp has
  been marked as having side effects for the same reason.
  TESTED = manually (trivial)
diff: @@ -105,8 +105,10 @@ retained with length 1.
  // In MLIR, the 'tf.Placeholder.input' instruction is used to capture attributes
  // of function arguments.
  +// Note: NoSideEffect trait is not added intentionally to preserve the captured
  +// attributes even if the input is unused.
  def TF_PlaceholderInputOp : TF_Op<"Placeholder.input",
  - [NoSideEffect, SameOperandsAndResultType]> {
  + [SameOperandsAndResultType]> {
  let summary = "PlaceholderInput op";
  let description = [{
  