When user enters two different password for a user the fields are only validated when the page is submitted, but after it fails the password cannot be changed.

Steps to reproduce:
1. Go to: Admin / Users / Administrator users
2. Edit Administrator user
3. In password field enter "qwe"
4. In confirm password field enter "123"

Expected:
"Passwords do not match" message appears (as it appears when creating a user).

Actual:
No message appears

5. Click "Update"

Result:
User is not updated. The "Username" field is cleared (and it's not editable and required), meaning that the page must be opened once again to edit the user.