fix: prevent worker starvation after max_execution_time restarts

Disable the execution timer in frankenphp_worker_request_shutdown() to
prevent stale timers from firing between requests. Also fix evaluation
order in frankenphp_handle_request() to check for shutdown before calling
frankenphp_worker_request_startup().

Fixes #2205

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dunglas

frankenphp.c

@@ -385,6 +385,12 @@ static void frankenphp_cleanup_worker_state(void) {
 
 /* Adapted from php_request_shutdown */
 static void frankenphp_worker_request_shutdown() {
+#ifdef ZEND_MAX_EXECUTION_TIMERS
+  /* Disable any execution timer set during the request callback to prevent
+   * stale timers from firing between requests */
+  zend_unset_timeout();
+#endif
+
   /* Flush all output buffers */
   zend_try { php_output_end_all(); }
   zend_end_try();
@@ -667,9 +673,7 @@ PHP_FUNCTION(frankenphp_handle_request) {
 
   struct go_frankenphp_worker_handle_request_start_return result =
       go_frankenphp_worker_handle_request_start(thread_index);
-  if (frankenphp_worker_request_startup() == FAILURE
-      /* Shutting down */
-      || !result.r0) {
+  if (!result.r0 || frankenphp_worker_request_startup() == FAILURE) {
     RETURN_FALSE;
   }