PartitionDurationFormatPattern: Unnecessary check for [[MillisecondsStyle]]

[anba]

PartitionDurationFormatPattern, steps 4.l.9.b.i-iii.:

i. Let nextValue be duration.[[Seconds]].
ii. Let nextDisplay be durationFormat.[[SecondsDisplay]].
iii. If durationFormat.[[MillisecondsStyle]] is "numeric", then
  i. Set nextValue to nextValue + duration.[[Milliseconds]] / 10³ + duration.[[Microseconds]] / 10⁶ + duration.[[Nanoseconds]] / 10⁹.

Can be simplified to:

i. Let nextValue be duration.[[Seconds]] + duration.[[Milliseconds]] / 10³ + duration.[[Microseconds]] / 10⁶ + duration.[[Nanoseconds]] / 10⁹.
ii. Let nextDisplay be durationFormat.[[SecondsDisplay]].

Because durationFormat.[[MillisecondsStyle]] is "numeric" is always true in this branch.