Expression test failures with node v10

[asheemmamoowala]

When upgrading from node v8 to node v10, the number-format expression tests (> yarn test-expressions number-format) are failing

number-format/currency

[
  "number-format",
  123456.789,
  {"locale": ["get", "locale"], "currency": ["get", "currency"]}
]
Difference:
Original
f([{},{"properties":{"locale":"ja-JP","currency":"JPY"}}])
**Expected: "Â¥123,457"**
**Actual: "JP¥ 123,457"**
f([{},{"properties":{"locale":"de-DE","currency":"EUR"}}])
**Expected: "€123,456.79"**
**Actual: "€ 123,456.79"**

number-format/precision

failed number-format/precision
[
  "number-format",
  987654321.2345679,
  {
    "locale": ["get", "locale"],
    "min-fraction-digits": ["get", "min"],
    "max-fraction-digits": ["get", "max"]
  }
]
Difference:
Original
f([{},{"properties":{"locale":"en-US","min":15,"max":20}}])
Expected: "987,654,321.234567900000000"
Actual: "987,654,321.234568000000000"