* Big Memory Leak in One Test
Many tests leak a little by not issuing disconnectWorksheets at the end. CellMatcherTest leaks a lot by opening a spreadsheet many times. Phpunit reported a high watermark of 390MB; fixing CellMatcherTest brings that figure down to 242MB. I have also changed it to use a formal assertion in many cases where markTestSkipped was (IMO inappropriately) used.
* Another Leak
Issue2301Test lacks a disconnect. Adding one reduces HWM from 242MB to 224.