test fail with cpu only

[tensor-tang]

issue

 make test
Running tests...
Test project /home/tangjian/paddle-tj/build
        Start   1: malloc_test
  1/310 Test   #1: malloc_test .....................................***Failed    0.01 sec
        Start   2: system_allocator_test
  2/310 Test   #2: system_allocator_test ...........................***Failed    0.01 sec
        Start   3: enforce_test
  3/310 Test   #3: enforce_test ....................................***Failed    0.01 sec
        Start   4: cpu_info_test
  4/310 Test   #4: cpu_info_test ...................................***Failed    0.01 sec
        Start   5: place_test
  5/310 Test   #5: place_test ......................................***Failed    0.01 sec
        Start   6: profiler_test
  6/310 Test   #6: profiler_test ...................................***Failed    0.01 sec
        Start   7: float16_test
  7/310 Test   #7: float16_test ....................................***Failed    0.01 sec
        Start   8: ddim_test
  8/310 Test   #8: ddim_test .......................................***Failed    0.01 sec
        Start   9: tensor_test
  9/310 Test   #9: tensor_test .....................................***Failed    0.01 sec
        Start  10: tensor_util_test
 10/310 Test  #10: tensor_util_test ................................***Failed    0.01 sec
        Start  11: eigen_test
 11/310 Test  #11: eigen_test ......................................***Failed    0.01 sec
        Start  12: lod_tensor_test
 12/310 Test  #12: lod_tensor_test .................................***Failed    0.01 sec
        Start  13: variable_test
 13/310 Test  #13: variable_test ...................................***Failed    0.01 sec
...

how to reproduce

cmake .. -DWITH_GPU=OFF -DWITH_FLUID_ONLY=ON -DWITH_TESTING=ON
make -j
make test

[tensor-tang]

This should be caused by mkldnn flag

make test ARGS='-R enforce_test -V
ERROR: unknown command line flag 'use_mkldnn' (via --fromenv or --tryfromenv)

[luotao1]

All the tests are OK in GPU version. Maybe there is something wrong in CPU version.