Fix issues #2009

[CainLuo]

[bug] ASCellNode has no background color in iOS 13

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[CainLuo]

Regarding the above issue, I found the specific problem, in the - (void)setElement:(ASCollectionElement *)element method of the ASTableView.mm file, the backgroundColor of node is used to set the _ ASTableViewCell's backgroundColor, I think this is incorrect, because node's backgroundColor should not be used to set as _ASTableViewCell's backgroundColor, but to open a separate property value of color to set separately. The temporary solution is to comment out self.backgroundColor = node.backgroundColor; and hope that it can be solved in subsequent versions of Texture. #2010

Before: No cellBackgroundColor property

After

ASCellNode.h add cellBackgroundColor

/* @abstract The inset of the cell background color
 * ASTableView uses these properties when configuring UITableViewCells that host ASCellNodes.
 */
@property UIColor *cellBackgroundColor;

ASTableNode.mm update setElement method:

- (void)setElement:(ASCollectionElement *)element
{
  _element = element;
  ASCellNode *node = element.node;
  
  if (node) {
    if (node.cellBackgroundColor != nil) {
        self.backgroundColor = node.cellBackgroundColor;
    }
    if (node.selectedBackgroundView != nil) {
        self.selectedBackgroundView = node.selectedBackgroundView;
    }
#if TARGET_OS_IOS
    self.separatorInset = node.separatorInset;
#endif
    self.selectionStyle = node.selectionStyle;
    self.focusStyle = node.focusStyle;
    self.accessoryType = node.accessoryType;

    if (node.tintColor != nil) {
        self.tintColor = node.tintColor;
    }

    // the following ensures that we clip the entire cell to it's bounds if node.clipsToBounds is set (the default)
    // This is actually a workaround for a bug we are seeing in some rare cases (selected background view
    // overlaps other cells if size of ASCellNode has changed.)
    self.clipsToBounds = node.clipsToBounds;
  }
  
  [node __setSelectedFromUIKit:self.selected];
  [node __setHighlightedFromUIKit:self.highlighted];
}

[CainLuo]

@Adlai-Holler Hello, I fixed a problem, but I can't seem to merge it, how can I fix it?