Similar to the removal of Map literal support, this is aimed at
simplifying the syntax and making it more consistent. Arrays are now
created using `Array.new`, which takes every value as a separate
argument:

    Array.new(10, 20, 30, ...)

To make this more pleasant to work with, the methods `StringBuffer.new`
and `ByteArray.new` now take a rest argument. This means you don't have
to write `ByteArray.new(Array.new(...))`, and instead can write
`ByteArray.new(...)`. For the `StringBuffer` type this requires that we
manually create an instance of it. To remove the need for using VM
instructions directly, we introduce `Object.allocate` as a wrapper
around this. This allows one to manually create instances like so:

    static def some_method {
      let instance = allocate

      instance.init(...)

      instance
    }