split with new file name doesn't open empty buffer

Describe the bug
:vs new_file_name.cc opens copy of current tab if new_file_name.cc doesn't exist

To Reproduce
Steps to reproduce the behavior:

1. Open any file in project folder
2. :vs new_file_name.cc where new_file_name.cc doesn't exist
3. VS Code complains about non-existing file and opens new tab with copy of current buffer

Expected behavior
In vim this opens new empty buffer which exists only in memory and will be saved as new_file_name.cc after you run :w

Screenshots
Error message and copy of existing buffer in VS Code:

New unsaved buffer in gvim:

Environment (please complete the following information):

• Issue Type: Bug
• Extension Name: vim
• Extension Version: 1.7.1
• OS Version: Linux x64 4.15.0-47-generic
• VSCode version: 1.33.1

{
	"messages": [],
	"activationTimes": {
		"startup": true,
		"codeLoadingTime": 383,
		"activateCallTime": 1,
		"activateResolvedTime": 137,
		"activationEvent": "*"
	},
	"runtimeErrors": []
}

Start by reproducing :vs new_file_name.cc in the VSCode Vim extension and compare it with Vim's behavior. Trace how the split command handles a path that does not exist; done means it opens an empty in-memory buffer and saves it under new_file_name.cc with :w.