message: Fix deref of undefined race on startup.
  This can happen if you interact with the editor while vim mode is still
  loading.
diff: @@ -685,7 +685,10 @@ export class ModeHandler implements vscode.Disposable {
  }
  // See comment about whatILastSetTheSelectionTo.
  - if (this._vimState.whatILastSetTheSelectionTo.isEqual(selection)) {
  + if (
  + this._vimState.whatILastSetTheSelectionTo &&
  + this._vimState.whatILastSetTheSelectionTo.isEqual(selection)
  + ) {
  return;
  }
  