Create tests around Somoa sate line change

[kolton-musgrove]

    it('Samoa date line change (add): 10:00PM 29 Dec 2011 -> 11:00PM 31 Dec 2011', () => {
      const timeZone = 'Pacific/Apia'
      const dayBeforeSamoaDateLineChangeAbs = timeZone.getInstantFor(dateTimeFns.fromNumbers(2011, 12, 29, 22))
      const start = dayBeforeSamoaDateLineChangeAbs.toZonedDateTimeISO(timeZone)
      const added = zonedDateTimeFns.add(start, { days: 1, hours: 1 })
      assert.equal(added.day, 31)
      assert.equal(added.hour, 23)
      assert.equal(added.minute, 0)
      const diff = zonedDateTimeFns.until(start, added, { largestUnit: 'days' })
      assert.equal(`${diff}`, 'P2DT1H')
      const undo = zonedDateTimeFns.subtract(added, diff)
      assert.equal(`${undo}`, `${start}`)
    })

    it('Samoa date line change (subtract): 11:00PM 31 Dec 2011 -> 10:00PM 29 Dec 2011', () => {
      const timeZone = 'Pacific/Apia'
      const dayAfterSamoaDateLineChangeAbs = timeZone.getInstantFor(dateTimeFns.fromNumbers(2011, 12, 31, 23))
      const start = dayAfterSamoaDateLineChangeAbs.toZonedDateTimeISO(timeZone)
      const skipped = start.subtract({ days: 1, hours: 1 })
      assert.equal(skipped.day, 31)
      assert.equal(skipped.hour, 22)
      assert.equal(skipped.minute, 0)
      const end = start.subtract({ days: 2, hours: 1 })
      assert.equal(end.day, 29)
      assert.equal(end.hour, 22)
      assert.equal(end.minute, 0)
      const diff = end.since(start, { largestUnit: 'days' })
      assert.equal(`${diff}`, '-P2DT1H')
      const undo = zonedDateTimeFns.add(start, diff)
      assert.equal(`${undo}`, `${end}`)
    })

The temporal proposal tests use functions to test the Somoa date line change that we do not implement (e.g. the timezone "type"). We should create tests around this.