Replay warnings during inheritance (#6928)

Since 3e6b447979 it is again possible to have
warnings (deprecations) during inheritance, and more such functionality is
likely in the future. This is a problem, because such warnings will only be
shown on the first request if the opcache inheritance cache is used. This
currently causes test failures in --repeat builds.

Fix this by uplifting the error recording functionality from opcache to Zend,
and then using it to persist a warning trace in the inheritance cache, which
can then be used to replay the warnings on subsequent executions.

Zend/zend_execute_API.c

@@ -188,6 +188,10 @@ void init_executor(void) /* {{{ */
 
 	EG(get_gc_buffer).start = EG(get_gc_buffer).end = EG(get_gc_buffer).cur = NULL;
 
+	EG(record_errors) = false;
+	EG(num_errors) = 0;
+	EG(errors) = NULL;
+
 	zend_fiber_init();
 	zend_weakrefs_init();