Fix test failure for init_fcall_003.phpt without opcache

If opcache isn't loaded, then opcache_invalidate() will fail.
Reproducible when you compile PHP without opcache, or run PHP without
opcache loaded, and try to run this test.

Closes phpGH-11378.

Author: ndossche

ext/opcache/tests/jit/init_fcall_003.phpt

@@ -11,6 +11,8 @@ opcache.jit_hot_loop=64
 opcache.jit_hot_func=127
 opcache.jit_hot_return=8
 opcache.jit_hot_side_exit=8
+--EXTENSIONS--
+opcache
 --FILE--
 <?php
 include(__DIR__ . '/init_fcall_003.inc');