Get KERNEL_DIR through $_ENV too for KernelTestCase

Author: yceruto

Test/KernelTestCase.php

@@ -105,8 +105,8 @@ private static function getPhpUnitCliConfigArgument()
      */
     protected static function getKernelClass()
     {
-        if (isset($_SERVER['KERNEL_DIR'])) {
-            $dir = $_SERVER['KERNEL_DIR'];
+        if (isset($_SERVER['KERNEL_DIR']) || isset($_ENV['KERNEL_DIR'])) {
+            $dir = isset($_SERVER['KERNEL_DIR']) ? $_SERVER['KERNEL_DIR'] : $_ENV['KERNEL_DIR'];
 
             if (!is_dir($dir)) {
                 $phpUnitDir = static::getPhpUnitXmlDir();