title: Why is systemLayoutSizeFittingSize returning (0, 0) for UITableViewCell?
body: <p>Here is the code snippet</p>
  
  <pre><code>    self.xyzIcon = [UIImage mobileImageNamed:@"icon_xyz"];
      self.xyzIconImageView = [UIImageView new];
      [self.contentView addSubview:self.xyzIconImageView];
  
      [self.xyzIconImageView mas_makeConstraints:^(MASConstraintMaker *make) {
          make.left.equalTo(weakSelf.contentView.mas_left);
          make.width.equalTo(@(weakSelf.xyzIcon.size.width));
          make.height.equalTo(@(weakSelf.xyzIcon.size.height));
      }];
  </code></pre>
  
  <p>In the view controller, which uses tableview</p>
  
  <pre><code>- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
      if (!self.prototypeCell) {
          self.prototypeCell = [UITableViewCell new];
      }
  
      [self.prototypeCell configure];
  
      CGFloat heightCalculated = [self.prototypeCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height + 1.f;
  
      NSLog(@"Height calculated %f", heightCalculated);
  
      returns heightCalculated; 
  }
  </code></pre>
  
  <p>This always returns 1.f. Please help and I am not sure what I am doing wrong here.</p>