builtin: call the C function wrappers instead of the C functions directly

[kimshrier]

builtin/array.v and builtin/map.v were calling C functions directly from a .v file which is now not allowed.

This converts those calls to using the wrapper functions in builtin/cfns_wrapper.c.v.

[tankf33der]

@kimshrier - this code works on master. What happened and what didn't work that made you come up with creating this PR?

fn main() {
	mut a := []int{len: 8,init: index}
	a[2] = 100

	b := a.sorted_with_compare(|x, y| *x - *y)
	println(b)
}

[JalonSolov]

V has a special check for C. routines in plain .v files. Those files either have to be renamed to .c.v, or V equivalent routines/wrappers need to replace the C. routines.

The plan has been to make including C. stuff in plain .v files an error.