In b6cd38ff055f003f92fff4c3e27d165fb4437057 we fixed the DatePipe so
that when it parsed date strings that looked like `YYYY-MM` it created a UTC
date that was not affected by the local timezone of the JavaScript engine.
This commit does the same for date strings of the form `YYYY`.
(Note that the previous commit, mentioned above, attempted to fix this case
too but the test was not actually checking the correct input string.)
Fixes#33944
PR Close#40620
PR Close#40629
ca0f6e6eed