docs: Remove automated List splitting and merging test

This was automated in WordPress/gutenberg#45048.

test-cases/gutenberg/writing-flow/splitting-merging.md

@@ -75,20 +75,3 @@ Start from an empty post.
 - Press enter two times to create an empty block in between 
 - Press back two times to merge everything again.
 - Check that the blocks were merged.
-
-
-##### TC006
-
-**Splitting/merge list block**
-
-- Write some items on a list block
-- Put the caret by the half of them (at the end of the item) and press Enter to create a new item.
-- Press Enter again to split the block into two, with an empty paragraph block in the middle. The paragraph block at the middle should be focused.
-- Write something on that newly created paragraph block.
-- Move the cursor to the beginning of the paragraph block
-- Press delete to merge the paragraph block with the upper list block.
-- Check that the new word should be a new list item.
-- Move the caret to the beginning of the second list block.
-- Press delete once to merge it back into the first list block.
-- Check that everything was merged and there’s just one list block.
-