message: remove duplicate check
  As shown by the function name `CompilationDisallowedByXlaCompileAttr`, I think we should respect `kXlaCompileAttr` first even if there is not a candidate JIT device. Actually,  the JIT device check is done again followed by this check.
diff: @@ -256,8 +256,7 @@ class MarkForCompilationPassImpl {
  // Nodes that XLA can compile are put in `compilation_candidates_`.
  Status FindCompilationCandidates();
  - bool CompilationDisallowedByXlaCompileAttr(Node* node,
  - const DeviceType& jit_device_type);
  + bool CompilationDisallowedByXlaCompileAttr(Node* node);
  // Populates `clusters_`.
  Status BuildInitialClusterSet();
  @@ -869,7 +868,7 @@ Status MarkForCompilationPassImpl::FindCompilationCandidates() {
  VLOG(4) << "Device type for " << node->name() << ": "
  << device_type.type_string();
  - if (CompilationDisallowedByXlaCompileAttr(node, device_type)) {
  + if (CompilationDisallowedByXlaCompileAttr(node)) {
  VLOG(2) << "Not clustering " << node->name()
  << ": disallowed by _XlaCompile attribute";
  continue;
  @@ -955,17 +954,11 @@ Status MarkForCompilationPassImpl::FindCompilationCandidates() {
  }
  bool MarkForCompilationPassImpl::CompilationDisallowedByXlaCompileAttr(
  - Node* node, const DeviceType& device_type) {
  + Node* node) {
  if (debug_options_.ignore_xla_compile_attr) {
  return false;
  }
  - const XlaOpRegistry::DeviceRegistration* registration;
  - if (!XlaOpRegistry::GetCompilationDevice(device_type.type(), &registration)) {
  - VLOG(2) << "Rejecting " << node->name() << ": could not find JIT device.";
  - return false;
  - }
  -
  // If there is a _XlaCompile annotation, use its value.
  bool compile = false;
  Status status = GetNodeAttr(node->attrs(), kXlaCompileAttr, &compile);
  