add unit test for test_adam_op_multi_thread

test=develop

python/paddle/fluid/tests/unittests/CMakeLists.txt

@@ -86,6 +86,7 @@ list(REMOVE_ITEM TEST_OPS test_nearest_interp_op)
 foreach(TEST_OP ${TEST_OPS})
     py_test_modules(${TEST_OP} MODULES ${TEST_OP})
 endforeach(TEST_OP)
+py_test_modules(test_adam_op_multi_thread MODULES test_adam_op ENVS FLAGS_inner_op_parallelism=4 FLAGS_min_param_size_to_use_multithread=2)
 py_test_modules(test_warpctc_op MODULES test_warpctc_op ENVS FLAGS_warpctc_dir=${WARPCTC_LIB_DIR} SERIAL)
 py_test_modules(test_bilinear_interp_op MODULES test_bilinear_interp_op SERIAL)
 py_test_modules(test_nearest_interp_op MODULES test_nearest_interp_op SERIAL)