WIP Table Destructor (#3707)

There is a circular reference between Worksheet and Table, which can lead to a memory leak. I tried to break this connection in the Worksheet destructor earlier, but this seemed to cause some sort of error with Phpunit 10 on Github, an error that I am unable to duplicate in my local environments. This PR will allow me to explore the problem to see if I can come up with any useful diagnostic data. If I get to a combination that works, I will consider merging it.

src/PhpSpreadsheet/Worksheet/Table.php

@@ -92,6 +92,14 @@ class Table
         $this->setName($name);
     }
 
+    /**
+     * Code to execute when this table is unset().
+     */
+    public function __destruct()
+    {
+        $this->workSheet = null;
+    }
+
     /**
      * Get Table name.
      */

src/PhpSpreadsheet/Worksheet/Worksheet.php

@@ -444,7 +444,7 @@ class Worksheet implements IComparable
 
         $this->disconnectCells();
         $this->rowDimensions = [];
-        //$this->removeTableCollection(); // problem with phpunit10
+        $this->tableCollection = new ArrayObject();
     }
 
     /**