fix test_KmaxSeqScore for only CPU compile.

paddle/gserver/tests/test_KmaxSeqScore.cpp

@@ -96,6 +96,11 @@ TEST(Layer, kmaxSeqScoreLayer) {
   MatrixPtr inValue =
       Matrix::create(subSeqStartPosition.back(), 1, false, false);
 
+  std::vector<bool> mode = {false};
+#ifndef PADDLE_ONLY_CPU
+  model.push_back(true);
+#endif
+
   for (auto hasSubseq : {false, true}) {
     vector<vector<int>> groundTruth;
     inValue->randomizeUniform();
@@ -104,7 +109,7 @@ TEST(Layer, kmaxSeqScoreLayer) {
                          hasSubseq ? subSeqStartPosition : seqStartPosition,
                          beamSize);
 
-    for (auto useGpu : {false, true}) {
+    for (auto useGpu : mode) {
       TestConfig config;
       config.layerConfig.set_type("kmax_seq_score");
       config.layerConfig.set_beam_size(beamSize);