message: [TF-XLA] Disable Tensorflow's CSE in xla compiler
  No need to do CSE in TF-XLA bridge, as XLA already has its own CSE pass later in the compilation pipeline. This removes one source of nondeterminism.
  RELNOTES: CSE pass from Tensorflow is now disabled in XLA.
diff: @@ -153,7 +153,8 @@ std::unique_ptr<Graph> XlaCompiler::GetGraph(const FunctionBody* fbody) {
  std::unique_ptr<Graph> graph(new Graph(options_.flib_def));
  CopyGraph(*fbody->graph, graph.get());
  OptimizerOptions opts;
  - opts.set_do_common_subexpression_elimination(true);
  + opts.set_opt_level(OptimizerOptions::L0);
  + opts.set_do_common_subexpression_elimination(false);
  opts.set_do_function_inlining(true);
  opts.set_do_constant_folding(true);
  GraphOptimizer optimizer(opts);
  @@ -184,8 +185,7 @@ Status XlaCompiler::CompileFunction(const XlaCompiler::CompileOptions& options,
  CheckSignature(fbody->arg_types, args),
  "Signature check failure while compiling: ", function.name());
  - std::unique_ptr<Graph> graph(new Graph(options_.flib_def));
  - CopyGraph(*fbody->graph, graph.get());
  + std::unique_ptr<Graph> graph = GetGraph(fbody);
  // _Arg and _Retval nodes don't exist in the stored subgraph for the function;
  // they are added by the function body looked up. Therefore, they don't have
  @@ -213,15 +213,6 @@ Status XlaCompiler::CompileFunction(const XlaCompiler::CompileOptions& options,
  *graph);
  }
  - // Optimize the graph before running the compiler.
  - OptimizerOptions opts;
  - opts.set_do_common_subexpression_elimination(true);
  - opts.set_do_function_inlining(true);
  - opts.set_do_constant_folding(true);
  - GraphOptimizer optimizer(opts);
  - optimizer.Optimize(flib_runtime_, flib_runtime_->env(),
  - /*device=*/nullptr, &graph, /*shape_map=*/nullptr);
  -
  VLOG(1) << "====================================================";
  TF_RETURN_IF_ERROR(
  CompileGraph(options, function_id, std::move(graph), args, result));
  