Fix assertInternalType deprecation in phpunit 9

Author: jderusse

Tests/CurrenciesTest.php

@@ -11,13 +11,16 @@
 
 namespace Symfony\Component\Intl\Tests;
 
+use Symfony\Bridge\PhpUnit\ForwardCompatTestTrait;
 use Symfony\Component\Intl\Currencies;
 
 /**
  * @group intl-data
  */
 class CurrenciesTest extends ResourceBundleTestCase
 {
+    use ForwardCompatTestTrait;
+
     // The below arrays document the state of the ICU data bundled with this package.
 
     private static $currencies = [
@@ -693,7 +696,7 @@ public function testGetFractionDigits($currency)
      */
     public function testGetRoundingIncrement($currency)
     {
-        $this->assertInternalType('numeric', Currencies::getRoundingIncrement($currency));
+        $this->assertIsNumeric(Currencies::getRoundingIncrement($currency));
     }
 
     public function provideCurrenciesWithNumericEquivalent()