message: [TF:MLIR:CPU] Change tfcompile-mlir to only invoke one graph pruning.
  Given the fact that tfcompile-mlir invokes PruneGraphDefInto, it should not need
  another graph pruning when calling ConvertGraphdefToMlir. This can also avoid
  hitting b/149215910.
diff: @@ -107,7 +107,7 @@ Status ConvertGraphDefToXlaViaMlir(GraphDef graph_def,
  TF_RETURN_IF_ERROR(PruneGraphDefInto(config, graph_def, &pruned_graph_def));
  GraphImportConfig specs;
  - specs.prune_unused_nodes = true;
  + specs.prune_unused_nodes = false;
  specs.convert_legacy_fed_inputs = false;
  specs.graph_as_function = false;
  specs.upgrade_legacy = false;
  