Avoid crash for reset/end/next/prev() on ffi classes

(And any PECLs returning `zend_empty_array` in the handler->get_properties
overrides)

Closes GH-9697

This is similar to the fix used in d9651a9
for array_walk.

This should make it safer for php-src (and PECLs, long-term) to return
the empty immutable array in `handler->get_properties` to avoid wasting memory.
See #9697 (comment)

The only possible internal iterator position for the empty array is at the end
of the empty array (nInternalPointer=0).
The `zend_hash*del*` helpers will always set nInternalPointer to 0 when an
array becomes empty,
regardless of previous insertions/deletions/updates to the array.

Author: TysonAndre

ext/standard/array.c

@@ -1102,6 +1102,10 @@ PHP_FUNCTION(end)
 		Z_PARAM_ARRAY_OR_OBJECT_HT_EX(array, 0, 1)
 	ZEND_PARSE_PARAMETERS_END();
 
+	if (zend_hash_num_elements(array) == 0) {
+		/* array->nInternalPointer is already 0 if the array is empty, even after removing elements */
+		RETURN_FALSE;
+	}
 	zend_hash_internal_pointer_end(array);
 
 	if (USED_RET()) {
@@ -1128,6 +1132,10 @@ PHP_FUNCTION(prev)
 		Z_PARAM_ARRAY_OR_OBJECT_HT_EX(array, 0, 1)
 	ZEND_PARSE_PARAMETERS_END();
 
+	if (zend_hash_num_elements(array) == 0) {
+		/* array->nInternalPointer is already 0 if the array is empty, even after removing elements */
+		RETURN_FALSE;
+	}
 	zend_hash_move_backwards(array);
 
 	if (USED_RET()) {
@@ -1154,6 +1162,10 @@ PHP_FUNCTION(next)
 		Z_PARAM_ARRAY_OR_OBJECT_HT_EX(array, 0, 1)
 	ZEND_PARSE_PARAMETERS_END();
 
+	if (zend_hash_num_elements(array) == 0) {
+		/* array->nInternalPointer is already 0 if the array is empty, even after removing elements */
+		RETURN_FALSE;
+	}
 	zend_hash_move_forward(array);
 
 	if (USED_RET()) {
@@ -1180,6 +1192,10 @@ PHP_FUNCTION(reset)
 		Z_PARAM_ARRAY_OR_OBJECT_HT_EX(array, 0, 1)
 	ZEND_PARSE_PARAMETERS_END();
 
+	if (zend_hash_num_elements(array) == 0) {
+		/* array->nInternalPointer is already 0 if the array is empty, even after removing elements */
+		RETURN_FALSE;
+	}
 	zend_hash_internal_pointer_reset(array);
 
 	if (USED_RET()) {