[FEATURE] Add support for Map Comprehension

[Starexify]

In haxe, we can use for/while loops on maps to fill them (as documented in the Haxe Manual.

This example code from there (comments match haxe behavior):

var a = [for (i in 0...5) i => 'number ${i}'];
trace(a); // {0 => number 0, 1 => number 1, 2 => number 2, 3 => number 3, 4 => number 4}
var i = 0;
var b = [while (i < 5) i => 'number ${i++}'];
trace(b); // {0 => number 0, 1 => number 1, 2 => number 2, 3 => number 3, 4 => number 4}

But in polymod this isn't supported and errors with:

 ERROR  Error while executing function WorstCParser.onCreate()#6: 
An unknown error occurred: hscriptClass(assets/scripts/WorstCParser.hxc):6: Invalid operator: =>