The global `$post` object for rows in the comments list table is polluted if `comment_post_ID` = 0

[rachelbaker]

In WP_Comments_List_Table->single_row() the global $post object is only set for each row if comment_post_ID > 0. In the column_response method the $post global is used to display the information about the related Post for each comment. If the comment_post_ID is 0 then this column displays the related Post information from the previous row that could return a valid Post object from the comment_post_ID.

[rachelbaker]

The third comment (from Moe) has a comment_post_ID of 0

[rachelbaker]

Looks like this was caused by r35674 from #34654. Also related: #33638

[rachelbaker]

Use the GLOBALS array when using unset()

[rachelbaker]

In 36339:

List Tables: Use the $GLOBALS array when unsetting the global post and comment in WP_Comments_List_Table::single_row().

In r35674 only the local variables were unset, when using unset() with a global variable the $GLOBALS array must be used.

Fixes #35506.