Editorial: Assert AddTime is called with a valid time

Author: anba

spec/plaintime.html

@@ -834,6 +834,7 @@ <h1>CompareTemporalTime ( _h1_, _min1_, _s1_, _ms1_, _mus1_, _ns1_, _h2_, _min2_
       <h1>AddTime ( _hour_, _minute_, _second_, _millisecond_, _microsecond_, _nanosecond_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, _nanoseconds_ )</h1>
       <emu-alg>
         1. Assert: _hour_, _minute_, _second_, _millisecond_, _microsecond_, _nanosecond_, _hours_, _minutes_, _seconds_, _milliseconds_, _microseconds_, and _nanoseconds_ are integers.
+        1. Assert: IsValidTime(_hour_, _minute_, _second_, _millisecond_, _microsecond_, _nanosecond_) is *true*.
         1. Let _hour_ be _hour_ + _hours_.
         1. Let _minute_ be _minute_ + _minutes_.
         1. Let _second_ be _second_ + _seconds_.