Add FromIterator trait implementation for Map struct

[Mr-Leshiy]

Need to add FromIterator trait implementation for Map struct.

llvm-js/collections/src/map.rs

Line 17 in 850f7dc

pub struct Map<K: Clone + Eq + Hash + Display, V> {

pub trait FromIterator<A> {
    fn [from_iter](https://doc.rust-lang.org/std/iter/trait.FromIterator.html#tymethod.from_iter)<T>(iter: T) -> Self
    where
        T: [IntoIterator](https://doc.rust-lang.org/std/iter/trait.IntoIterator.html)<Item = A>;
}