([node isVertical] != [parentSplit isVertical]

To repro:

1. Create three splits like this:

+------+------+
|      |  2   |
|  1   +------+
|      |  3   |
+------+------+

2. Close #1 (closed)

+-------------+
|      2      |
+-------------+
|      3      |
+-------------+

3. Undo close. Note the layout is wrong.

+-------------+
|      1      |
+-------------+
|      2      |
+-------------+
|      3      |
+-------------+

4. Cause a broken pipe in 2

+-------------+
|      1      |
+-------------+
| Broken pipe |
|      2      |
+-------------+
|      3      |
+-------------+

5. cmd-w to close 2. Assertion or critical error happens.

+-------------+
|      1      |
+-------------+
| Broken pipe |
|      2      |     <- Cmd-W this pane
+-------------+
|      3      |
+-------------+

closed