cgen: fix array map to fixed array (fix #23116)

[yuyi98]

This PR fix array map to fixed array (fix #23116).

• Fix array map to fixed array.
• Add test.

module main

type Mat4 = [16]f32

struct GameObject  {
mut:
	transform Mat4
	children []&GameObject
}

fn main() {
	mut v1 := &GameObject{}
	eprintln("children: ${v1.children.map(it.transform)}")
	assert '${v1.children.map(it.transform)}' == '[]'
}

PS D:\Test\v\tt1> v run .    
children: []

_{Huly®: V_0.6-21555}

[spytheman]

Excellent work.