Drop reimplementations of is_iterable() & iterator_to_array()

Especially the SimpleCacheWithBagOStuff class is unnecessarily
complex for no obvious reason.

iterator_to_array() apparently exists since PHP 5.1.

is_iterable() exists since PHP 7.1.

Note the int/string validation was done twice before. This is all
very well covered by PHPUnit tests. Pretty much guaranteed
everything behaves exactly as before.

Change-Id: I9fe716ab438ac27cd9af12e91275705ae796bde3

Author: thiemowmde

src/ByPropertyIdArray.php

@@ -61,7 +61,7 @@ class ByPropertyIdArray extends ArrayObject {
 	 * @throws InvalidArgumentException
 	 */
 	public function __construct( $input = null ) {
-		if ( is_object( $input ) && !( $input instanceof Traversable ) ) {
+		if ( $input && !is_iterable( $input ) ) {
 			throw new InvalidArgumentException( '$input must be an array, Traversable or null' );
 		}
 

src/Internal/MapValueHasher.php

@@ -32,7 +32,7 @@ public function __construct( $holdOrderIntoAccount = false ) {
 	 * @throws InvalidArgumentException
 	 */
 	public function hash( $map ) {
-		if ( !is_array( $map ) && !( $map instanceof Traversable ) ) {
+		if ( !is_iterable( $map ) ) {
 			throw new InvalidArgumentException( '$map must be an array or an instance of Traversable' );
 		}
 

src/ReferenceList.php

@@ -37,7 +37,7 @@ class ReferenceList implements Countable, IteratorAggregate, Serializable {
 	 * @throws InvalidArgumentException
 	 */
 	public function __construct( $references = [] ) {
-		if ( !is_array( $references ) && !( $references instanceof Traversable ) ) {
+		if ( !is_iterable( $references ) ) {
 			throw new InvalidArgumentException( '$references must be an array or an instance of Traversable' );
 		}
 

src/SiteLinkList.php

@@ -35,7 +35,7 @@ class SiteLinkList implements IteratorAggregate, Countable {
 	 * @throws InvalidArgumentException
 	 */
 	public function __construct( /* iterable */ $siteLinks = [] ) {
-		if ( !is_array( $siteLinks ) && !( $siteLinks instanceof Traversable ) ) {
+		if ( !is_iterable( $siteLinks ) ) {
 			throw new InvalidArgumentException( '$siteLinks must be iterable' );
 		}
 

src/Snak/SnakList.php

@@ -37,7 +37,7 @@ class SnakList extends ArrayObject {
 	 * @throws InvalidArgumentException
 	 */
 	public function __construct( $snaks = [] ) {
-		if ( !is_array( $snaks ) && !( $snaks instanceof Traversable ) ) {
+		if ( !is_iterable( $snaks ) ) {
 			throw new InvalidArgumentException( '$snaks must be an array or an instance of Traversable' );
 		}