Fix use statement order

Author: jmikola

tests/Exception/InvalidArgumentExceptionTest.php

@@ -2,11 +2,10 @@
 
 namespace MongoDB\Tests\Exception;
 
+use AssertionError;
 use MongoDB\Exception\InvalidArgumentException;
 use MongoDB\Tests\TestCase;
 
-use AssertionError;
-
 class InvalidArgumentExceptionTest extends TestCase
 {
     /**