N°2651 rollback gitignore for lib tests dirs

Too dangerous ! We'll work properly on this but for 2.8

lib/nikic/php-parser/test/PhpParser/ErrorHandler/ThrowingTest.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace PhpParser\ErrorHandler;
+
+use PhpParser\Error;
+
+class ThrowingTest extends \PHPUnit_Framework_TestCase {
+    /**
+     * @expectedException \PhpParser\Error
+     * @expectedExceptionMessage Test
+     */
+    public function testHandleError() {
+        $errorHandler = new Throwing();
+        $errorHandler->handleError(new Error('Test'));
+    }
+}