Sometimes cannot undo

[schontz]

Describe the bug
Sometimes undo u does not work and I get the following error:

TaskQueue: Error running task. Failed to handle key=u. Cannot read property 'getTime' of undefined.

To Reproduce
I am not sure how to reproduce it. If there is a way to turn on logging I am happy to do so and report.

Expected behavior
Undo works.

Environment (please complete the following information):

• Extension Name: vim
• Extension Version: 1.12.2
• OS Version: Darwin x64 18.7.0
• VSCode version: 1.40.2

{
	"messages": [],
	"activationTimes": {
		"codeLoadingTime": 628,
		"activateCallTime": 4,
		"activateResolvedTime": 775,
		"activationReason": {
			"startup": true,
			"extensionId": {
				"value": "vscodevim.vim",
				"_lower": "vscodevim.vim"
			},
			"activationEvent": "*"
		}
	},
	"runtimeErrors": []
}

Additional context
Add any other context about the problem here.

[J-Fields]

Duplicate of #4351. This is fixed and will be in a new patch release soon.