[cherry-pick] Fix bug of building InferMetaContext (#42211) (#42399)

* fix bug of building InferMetaContext (#42211)

* add unitest

paddle/fluid/framework/infershape_utils.cc

@@ -558,10 +558,7 @@ CompatInferMetaContext BuildInferMetaContext(InferShapeContext* ctx,
               }
 
               if (num_ele <= 0) {
-                PADDLE_THROW(platform::errors::Unimplemented(
-                    "Invalid number for construct phi::IntArray, expected "
-                    "number > 0, but actually is %d. ",
-                    num_ele));
+                num_ele = tensor_dims.size();
               }
 
             } else {

python/paddle/fluid/tests/unittests/test_empty_op.py

@@ -232,28 +232,33 @@ class TestEmptyAPI(unittest.TestCase):
             name="shape_tensor_int32", shape=[2], dtype="int32")
         shape_tensor_int64 = fluid.data(
             name="shape_tensor_int64", shape=[2], dtype="int64")
+        shape_tensor_unknown = fluid.data(
+            name="shape_tensor_unknown", shape=[-1], dtype="int64")
 
         out_1 = paddle.empty(shape=[200, 3], dtype=dtype)
         out_2 = paddle.empty(shape=shape_tensor_int32, dtype=dtype)
         out_3 = paddle.empty(shape=shape_tensor_int64, dtype=dtype)
         out_4 = paddle.empty(shape=[200, positive_2_int32], dtype=dtype)
         out_5 = paddle.empty(shape=[200, positive_2_int64], dtype=dtype)
+        out_6 = paddle.empty(shape=shape_tensor_unknown, dtype=dtype)
 
         place = paddle.CPUPlace()
         exe = paddle.static.Executor(place)
-        res_1, res_2, res_3, res_4, res_5 = exe.run(
+        res_1, res_2, res_3, res_4, res_5, res_6 = exe.run(
             fluid.default_main_program(),
             feed={
                 "shape_tensor_int32": np.array([200, 3]).astype("int32"),
                 "shape_tensor_int64": np.array([200, 3]).astype("int64"),
+                "shape_tensor_unknown": np.array([200, 3]).astype("int64"),
             },
-            fetch_list=[out_1, out_2, out_3, out_4, out_5])
+            fetch_list=[out_1, out_2, out_3, out_4, out_5, out_6])
 
         self.__check_out__(res_1, dtype)
         self.__check_out__(res_2, dtype)
         self.__check_out__(res_3, dtype)
         self.__check_out__(res_4, dtype)
         self.__check_out__(res_5, dtype)
+        self.__check_out__(res_6, dtype)
 
 
 class TestEmptyError(unittest.TestCase):