Fix assertion

Fixes oss-fuzz #65233

Author: dstogov

Zend/zend_opcode.c

@@ -867,12 +867,12 @@ static bool keeps_op1_alive(zend_op *opline) {
 	 || opline->opcode == ZEND_SWITCH_STRING
 	 || opline->opcode == ZEND_MATCH
 	 || opline->opcode == ZEND_FETCH_LIST_R
+	 || opline->opcode == ZEND_FETCH_LIST_W
 	 || opline->opcode == ZEND_COPY_TMP) {
 		return 1;
 	}
 	ZEND_ASSERT(opline->opcode != ZEND_FE_FETCH_R
 		&& opline->opcode != ZEND_FE_FETCH_RW
-		&& opline->opcode != ZEND_FETCH_LIST_W
 		&& opline->opcode != ZEND_VERIFY_RETURN_TYPE
 		&& opline->opcode != ZEND_BIND_LEXICAL
 		&& opline->opcode != ZEND_ROPE_ADD);

ext/opcache/tests/opt/dce_014.phpt

@@ -0,0 +1,12 @@
+--TEST--
+DCE may remove FREE after FETCH_LIST_W
+--FILE--
+<?php
+function () {
+    $a = $r[][] = $r = [] & $y;
+    +list(&$y) = $a;
+}
+?>
+DONE
+--EXPECT--
+DONE