bug #119 Update is_countable to include countable objects that doesn'…

…t implement \Countable (pierredup)

This PR was merged into the 1.8-dev branch.

Discussion
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Update is_countable to include countable objects that doesn't implement \Countable

Some objects are countable but don't implement `Countable` ([symfony/polyfill#115#issuecomment-384361414](symfony/polyfill#115 (comment)))

The objects that I could identify that is countable is `ResourceBundle` and `SimpleXmlElement`

Commits
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b53929e Update is_countable to include countable objects that doesn't implement \Countable

bootstrap.php

@@ -11,6 +11,6 @@
 
 if (PHP_VERSION_ID < 70300) {
     if (!function_exists('is_countable')) {
-        function is_countable($var) { return is_array($var) || $var instanceof Countable; }
+        function is_countable($var) { return is_array($var) || $var instanceof Countable || $var instanceof ResourceBundle || $var instanceof SimpleXmlElement; }
     }
 }