src/vs/editor/common/core/selection.ts/Selection/selectionsArrEqual
class Selection:	public static selectionsArrEqual(a: ISelection[], b: ISelection[]): boolean {
		if (a && !b || !a && b) {
			return false;
		}
		if (!a && !b) {
			return true;
		}
		if (a.length !== b.length) {
			return false;
		}
		for (let i = 0, len = a.length; i < len; i++) {
			if (!this.selectionsEqual(a[i], b[i])) {
				return false;
			}
		}
		return true;
	}