Editorial: Remove unnecessary checks for undefined before ToPositiveI…

…nteger

`ToPositiveInteger(undefined)` calls
`ToIntegerThrowOnInfinity(undefined)`, which in turn calls
`ToIntegerOrInfinity(undefined)`, which in turn calls
`ToNumber(undefined)`. `ToNumber` returns `NaN`, `ToIntegerOrInfinity`
then returns `0`, `ToIntegerThrowOnInfinity` returns `0` unchanged, and
finally `ToPositiveInteger` will throw a RangeError for `0`. That means
it's not necessary to handle `undefined` before calling
`ToPositiveInteger`.

spec/calendar.html

@@ -166,7 +166,6 @@ <h1>CalendarMonth ( _calendar_, _dateLike_ )</h1>
       <emu-alg>
         1. Assert: Type(_calendar_) is Object.
         1. Let _result_ be ? Invoke(_calendar_, *"month"*, « _dateLike_ »).
-        1. If _result_ is *undefined*, throw a *RangeError* exception.
         1. Return ? ToPositiveInteger(_result_).
       </emu-alg>
     </emu-clause>
@@ -192,7 +191,6 @@ <h1>CalendarDay ( _calendar_, _dateLike_ )</h1>
       <emu-alg>
         1. Assert: Type(_calendar_) is Object.
         1. Let _result_ be ? Invoke(_calendar_, *"day"*, « _dateLike_ »).
-        1. If _result_ is *undefined*, throw a *RangeError* exception.
         1. Return ? ToPositiveInteger(_result_).
       </emu-alg>
     </emu-clause>