message: Fix compute constant test
  DynamicDimensionSize has become S32, this change fixes the test cases.
diff: @@ -160,7 +160,7 @@ TEST_F(ComputeConstantTest, GetDimensionSize) {
  auto get_dimension_size = GetDimensionSize(add, 0);
  EXPECT_TRUE(IsConstant(get_dimension_size, &b));
  - TF_ASSERT_OK_AND_ASSIGN(auto value, ComputeConstantScalar<uint32>(
  + TF_ASSERT_OK_AND_ASSIGN(auto value, ComputeConstantScalar<int32>(
  client, get_dimension_size, &b));
  EXPECT_EQ(value, 1);
  }
  @@ -178,7 +178,7 @@ TEST_F(ComputeConstantTest, MultipleGetDimensionSize) {
  EXPECT_TRUE(IsConstant(add_2, &b));
  TF_ASSERT_OK_AND_ASSIGN(auto value,
  - ComputeConstantScalar<uint32>(client, add_2, &b));
  + ComputeConstantScalar<int32>(client, add_2, &b));
  EXPECT_EQ(value, 2);
  }
  }
  