LibJS: Remove assertions that are now part of structured headers

This is an editorial change in the Temporal spec.

See:
- 7fbdd28
- f666243
- 8c7d066
- 307d108
- d9ca402

In practical terms this means we can now get rid of a couple of awkward
assertion steps that were no-ops anyway, since the types are enforced
by the compiler.

Userland/Libraries/LibJS/Runtime/Temporal/PlainTime.cpp

@@ -42,33 +42,31 @@ void PlainTime::visit_edges(Visitor& visitor)
 // 4.5.1 DifferenceTime ( h1, min1, s1, ms1, mus1, ns1, h2, min2, s2, ms2, mus2, ns2 ), https://tc39.es/proposal-temporal/#sec-temporal-differencetime
 TimeDurationRecord difference_time(u8 hour1, u8 minute1, u8 second1, u16 millisecond1, u16 microsecond1, u16 nanosecond1, u8 hour2, u8 minute2, u8 second2, u16 millisecond2, u16 microsecond2, u16 nanosecond2)
 {
-    // Assert: h1, min1, s1, ms1, mus1, ns1, h2, min2, s2, ms2, mus2, and ns2 are integers.
-
-    // 2. Let hours be h2 − h1.
+    // 1. Let hours be h2 − h1.
     auto hours = hour2 - hour1;
 
-    // 3. Let minutes be min2 − min1.
+    // 2. Let minutes be min2 − min1.
     auto minutes = minute2 - minute1;
 
-    // 4. Let seconds be s2 − s1.
+    // 3. Let seconds be s2 − s1.
     auto seconds = second2 - second1;
 
-    // 5. Let milliseconds be ms2 − ms1.
+    // 4. Let milliseconds be ms2 − ms1.
     auto milliseconds = millisecond2 - millisecond1;
 
-    // 6. Let microseconds be mus2 − mus1.
+    // 5. Let microseconds be mus2 − mus1.
     auto microseconds = microsecond2 - microsecond1;
 
-    // 7. Let nanoseconds be ns2 − ns1.
+    // 6. Let nanoseconds be ns2 − ns1.
     auto nanoseconds = nanosecond2 - nanosecond1;
 
-    // 8. Let sign be ! DurationSign(0, 0, 0, 0, hours, minutes, seconds, milliseconds, microseconds, nanoseconds).
+    // 7. Let sign be ! DurationSign(0, 0, 0, 0, hours, minutes, seconds, milliseconds, microseconds, nanoseconds).
     auto sign = duration_sign(0, 0, 0, 0, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
 
-    // 9. Let bt be ! BalanceTime(hours × sign, minutes × sign, seconds × sign, milliseconds × sign, microseconds × sign, nanoseconds × sign).
+    // 8. Let bt be ! BalanceTime(hours × sign, minutes × sign, seconds × sign, milliseconds × sign, microseconds × sign, nanoseconds × sign).
     auto bt = balance_time(hours * sign, minutes * sign, seconds * sign, milliseconds * sign, microseconds * sign, nanoseconds * sign);
 
-    // 10. Return the Record { [[Days]]: bt.[[Days]] × sign, [[Hours]]: bt.[[Hour]] × sign, [[Minutes]]: bt.[[Minute]] × sign, [[Seconds]]: bt.[[Second]] × sign, [[Milliseconds]]: bt.[[Millisecond]] × sign, [[Microseconds]]: bt.[[Microsecond]] × sign, [[Nanoseconds]]: bt.[[Nanosecond]] × sign }.
+    // 9. Return the Record { [[Days]]: bt.[[Days]] × sign, [[Hours]]: bt.[[Hour]] × sign, [[Minutes]]: bt.[[Minute]] × sign, [[Seconds]]: bt.[[Second]] × sign, [[Milliseconds]]: bt.[[Millisecond]] × sign, [[Microseconds]]: bt.[[Microsecond]] × sign, [[Nanoseconds]]: bt.[[Nanosecond]] × sign }.
     return TimeDurationRecord { .days = static_cast<double>(bt.days * sign), .hours = static_cast<double>(bt.hour * sign), .minutes = static_cast<double>(bt.minute * sign), .seconds = static_cast<double>(bt.second * sign), .milliseconds = static_cast<double>(bt.millisecond * sign), .microseconds = static_cast<double>(bt.microsecond * sign), .nanoseconds = static_cast<double>(bt.nanosecond * sign) };
 }