Create array with size determined at runtime

[KrisV-777]

Being able to allocate arrays dynamically without relying on a script extender wrapper functions,

int i = 4
int[] a = new int[i]

[erri120]

The op-code for array creation requires a constant size. This is a limitation imposed by the PEX format and can only be solved by very hacky solutions. I will leave this issue open for now, but this is not something that can easily be added by a compiler.