Reflect.getProperty for Array.contains returns undefined in JS

**Reproduction:** https://try.haxe.org/#00086a9F

The example demonstrates the use of `Reflect.getProperty` to attempt to retrieve the `Array.contains` function, which should be available on all platforms, and finds that it is not available on JavaScript specifically.

**Steps:**
- Go to `Options`, and select `Eval` as the `Target`, then click `Build and Run`. The result is `#closure : true`
- Go to `Options`, and select `JavaScript` as the `Target`, then click `Build and Run`. The result is `undefined : false`

**Expectation:** Reflect should function properly on the JavaScript platform.