[HttpKernel] Add parameters kernel.runtime_mode and kernel.runtime_mode.*, all set from env var APP_RUNTIME_MODE

Author: nicolas-grekas

Debug.php

@@ -22,7 +22,7 @@ public static function enable(): ErrorHandler
     {
         error_reporting(-1);
 
-        if (!\in_array(\PHP_SAPI, ['cli', 'phpdbg'], true)) {
+        if (!\in_array(\PHP_SAPI, ['cli', 'phpdbg', 'embed'], true)) {
             ini_set('display_errors', 0);
         } elseif (!filter_var(\ini_get('log_errors'), \FILTER_VALIDATE_BOOL) || \ini_get('error_log')) {
             // CLI - display errors only if they're not already logged to STDERR

ErrorHandler.php

@@ -640,7 +640,7 @@ public static function handleFatalError(array $error = null): void
      */
     private function renderException(\Throwable $exception): void
     {
-        $renderer = \in_array(\PHP_SAPI, ['cli', 'phpdbg'], true) ? new CliErrorRenderer() : new HtmlErrorRenderer($this->debug);
+        $renderer = \in_array(\PHP_SAPI, ['cli', 'phpdbg', 'embed'], true) ? new CliErrorRenderer() : new HtmlErrorRenderer($this->debug);
 
         $exception = $renderer->render($exception);