message: Remove restriction of lowering tf_device.replicate to islands if replicate body contains a parallel_execute.
  TPU rewrite has been updated to generate parallel_execute that may be replicated, for model parallelism.
diff: @@ -163,9 +163,6 @@ LogicalResult CreateIslandsFromReplicate(const Dialect* tf_dialect,
  tf_device::ReplicateOp replicate_op) {
  OpBuilder builder(island_op);
  const int num_replicas = replicate_op.n().getLimitedValue();
  - if (!replicate_op.GetBody().getOps<tf_device::ParallelExecuteOp>().empty())
  - return replicate_op.emitError()
  - << "TPU computation with multiple logical cores is not supported.";
  // Create islands per replica.
  llvm::SmallVector<tf_executor::IslandOp, 8> replicas =
  