Ensure vm_spec_handlers exists for all opcodes <= 255 so that user defined higher opcodes do not read outside buffer

This largely has no effect in practice, but ASAN will complain then.

Author: bwoebi

Zend/zend_vm_execute.h

@@ -63870,7 +63870,59 @@ void zend_vm_init(void)
 		2542,
 		2543,
 		2544,
-		3448
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
+		3448,
 	};
 #if (ZEND_VM_KIND == ZEND_VM_KIND_HYBRID)
 	zend_opcode_handler_funcs = labels;

Zend/zend_vm_gen.php

@@ -1525,7 +1525,9 @@ function gen_specs($f, $prolog, $specs) {
         $last = $num;
         out($f, "$prolog$def,\n");
     }
-    out($f, "$prolog$lastdef\n");
+    while ($last++ < 255) {
+        out($f, "$prolog$lastdef,\n");
+    }
 }
 
 // Generates handler for undefined opcodes (CALL threading model)